@article {pmid30648935,
year = {2019},
author = {Soto, W and Travisano, M and Tolleson, AR and Nishiguchi, MK},
title = {Symbiont evolution during the free-living phase can improve host colonization.},
journal = {Microbiology (Reading, England)},
volume = {},
number = {},
pages = {},
doi = {10.1099/mic.0.000756},
pmid = {30648935},
issn = {1465-2080},
abstract = {For micro-organisms cycling between free-living and host-associated stages, where reproduction occurs in both of these lifestyles, an interesting inquiry is whether evolution during the free-living stage can be positively pleiotropic to microbial fitness in a host environment. To address this topic, the squid host Euprymna tasmanica and the marine bioluminescent bacterium Vibrio fischeri were utilized. Microbial ecological diversification in static liquid microcosms was used to simulate symbiont evolution during the free-living stage. Thirteen genetically distinct V. fischeri strains from a broad diversity of ecological sources (e.g. squid light organs, fish light organs and seawater) were examined to see if the results were reproducible in many different genetic settings. Genetic backgrounds that are closely related can be predisposed to considerable differences in how they respond to similar selection pressures. For all strains examined, new mutations with striking and facilitating effects on host colonization arose quickly during microbial evolution in the free-living stage, regardless of the ecological context under consideration for a strain's genetic background. Microbial evolution outside a host environment promoted host range expansion, improved host colonization for a micro-organism, and diminished the negative correlation between biofilm formation and motility.},
}
@article {pmid30635418,
year = {2019},
author = {Belcaid, M and Casaburi, G and McAnulty, SJ and Schmidbaur, H and Suria, AM and Moriano-Gutierrez, S and Pankey, MS and Oakley, TH and Kremer, N and Koch, EJ and Collins, AJ and Nguyen, H and Lek, S and Goncharenko-Foster, I and Minx, P and Sodergren, E and Weinstock, G and Rokhsar, DS and McFall-Ngai, M and Simakov, O and Foster, JS and Nyholm, SV},
title = {Symbiotic organs shaped by distinct modes of genome evolution in cephalopods.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {},
number = {},
pages = {},
doi = {10.1073/pnas.1817322116},
pmid = {30635418},
issn = {1091-6490},
abstract = {Microbes have been critical drivers of evolutionary innovation in animals. To understand the processes that influence the origin of specialized symbiotic organs, we report the sequencing and analysis of the genome of Euprymna scolopes, a model cephalopod with richly characterized host-microbe interactions. We identified large-scale genomic reorganization shared between E. scolopes and Octopus bimaculoides and posit that this reorganization has contributed to the evolution of cephalopod complexity. To reveal genomic signatures of host-symbiont interactions, we focused on two specialized organs of E. scolopes: the light organ, which harbors a monoculture of Vibrio fischeri, and the accessory nidamental gland (ANG), a reproductive organ containing a bacterial consortium. Our findings suggest that the two symbiotic organs within E. scolopes originated by different evolutionary mechanisms. Transcripts expressed in these microbe-associated tissues displayed their own unique signatures in both coding sequences and the surrounding regulatory regions. Compared with other tissues, the light organ showed an abundance of genes associated with immunity and mediating light, whereas the ANG was enriched in orphan genes known only from E. scolopes Together, these analyses provide evidence for different patterns of genomic evolution of symbiotic organs within a single host.},
}
@article {pmid30506600,
year = {2018},
author = {Wasilko, NP and Larios-Valencia, J and Steingard, CH and Nunez, BM and Verma, SC and Miyashiro, T},
title = {Sulfur availability for Vibrio fischeri growth during symbiosis establishment depends on biogeography within the squid light organ.},
journal = {Molecular microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/mmi.14177},
pmid = {30506600},
issn = {1365-2958},
abstract = {The fitness of host-associated microbes depends on their ability to access nutrients in vivo. Identifying these mechanisms is significant for understanding how microbes have evolved to fill specific ecological niches within a host. Vibrio fischeri is a bioluminescent bacterium that colonizes and proliferates within the light organ of the Hawaiian bobtail squid, which provides an opportunity to study how bacteria grow in vivo. Here, the transcription factor CysB is shown to be necessary for V. fischeri both to grow on several sulfur sources in vitro and to establish symbiosis with juvenile squid. CysB is also found to regulate several genes involved in sulfate assimilation and to contribute to the growth of V. fischeri on cystine, which is the oxidized form of cysteine. A mutant that grows on cystine but not sulfate could establish symbiosis, suggesting that V. fischeri acquires nutrients related to this compound within the host. Finally, CysB-regulated genes are shown to be differentially expressed among the V. fischeri populations occupying the various colonization sites found within the light organ. Together, these results suggest the biogeography of V. fischeri populations within the squid light organ impacts the physiology of this symbiotic bacterium in vivo through CysB-dependent gene regulation. This article is protected by copyright. All rights reserved.},
}
@article {pmid30121851,
year = {2018},
author = {Houyvet, B and Zanuttini, B and Corre, E and Le Corguillé, G and Henry, J and Zatylny-Gaudin, C},
title = {Design of antimicrobial peptides from a cuttlefish database.},
journal = {Amino acids},
volume = {50},
number = {11},
pages = {1573-1582},
doi = {10.1007/s00726-018-2633-4},
pmid = {30121851},
issn = {1438-2199},
mesh = {Animals ; *Antimicrobial Cationic Peptides/chemical synthesis/chemistry/pharmacology ; Bacteria/*growth & development ; *Databases, Protein ; Decapodiformes/*chemistry ; },
abstract = {No antimicrobial peptide has been identified in cephalopods to date. Annotation of transcriptomes or genomes using basic local alignment Search Tool failed to yield any from sequence identities. Therefore, we searched for antimicrobial sequences in the cuttlefish (Sepia officinalis) database by in silico analysis of a transcriptomic database. Using an original approach based on the analysis of cysteine-free antimicrobial peptides selected from our Antimicrobial Peptide Database (APD3), the online prediction tool of the Collection of Anti-Microbial Peptides (CAMPR3), and a homemade software program, we identified potential antibacterial sequences. Nine peptides less than 25 amino acids long were synthesized. The hydrophobic content of all nine of them ranged from 30 to 70%, and they could form alpha-helices. Three peptides possessed similarities with piscidins, one with BMAP-27, and five were totally new. Their antibacterial activity was evaluated on eight bacteria including the aquatic pathogens Vibrio alginolyticus, Aeromonas salmonicida, or human pathogens such as Salmonella typhimurium, Listeria monocytogenes, or Staphylococcus aureus. Despite the prediction of an antimicrobial potential for eight of the peptides, only two-GR21 and KT19-inhibited more than one bacterial strain with minimal inhibitory concentrations below 25 µM. Some sequences like VA20 and FK19 were hemolytic, while GR21 induced less than 10% of hemolysis on human blood cells at a concentration of 200 µM. GR21 was the only peptide derived from a precursor with a signal peptide, suggesting a real role in cuttlefish immune defense.},
}
@article {pmid30427559,
year = {2018},
author = {Stabb, EV},
title = {Should they stay or should they go? Nitric oxide and the clash of regulators governing Vibrio fischeri biofilm formation.},
journal = {Molecular microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/mmi.14163},
pmid = {30427559},
issn = {1365-2958},
abstract = {A key regulatory decision for many bacteria is the switch between biofilm formation and motile dispersal, and this dynamic is well illustrated in the light-organ symbiosis between the bioluminescent bacterium Vibrio fischeri and the Hawaiian bobtail squid. Biofilm formation mediated by the syp gene cluster helps V. fischeri transition from a dispersed planktonic lifestyle to a robust aggregate on the surface of the nascent symbiotic organ. However, the bacteria must then swim to pores and down into the deeper crypt tissues that they ultimately colonize. A number of positive and negative regulators control syp expression and biofilm formation, but until recently the environmental inputs controlling this clash between opposing regulatory mechanisms have been unclear. Thompson et al. have now shown that Syp-mediated biofilms can be repressed by a well known host-derived molecule: nitric oxide. This regulation is accomplished by the NO sensor HnoX exerting control over the biofilm regulator HahK. The discoveries reported here by Thompson et al. cast new light on a critical early stage of symbiotic initiation in the V. fischeri-squid model symbiosis, and more broadly it adds to a growing understanding of the role(s) that NO and HnoX play in biofilm regulation by many bacteria. This article is protected by copyright. All rights reserved.},
}
@article {pmid30353039,
year = {2018},
author = {Bongrand, C and Ruby, EG},
title = {Achieving a multi-strain symbiosis: strain behavior and infection dynamics.},
journal = {The ISME journal},
volume = {},
number = {},
pages = {},
doi = {10.1038/s41396-018-0305-8},
pmid = {30353039},
issn = {1751-7370},
support = {GM099507//U.S. Department of Health & Human Services | NIH | National Institute of General Medical Sciences (NIGMS)/ ; GM099507//U.S. Department of Health & Human Services | NIH | National Institute of General Medical Sciences (NIGMS)/ ; AI050661//U.S. Department of Health & Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; AI050661//U.S. Department of Health & Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; OD011024//U.S. Department of Health & Human Services | NIH | NIH Office of the Director (OD)/ ; OD011024//U.S. Department of Health & Human Services | NIH | NIH Office of the Director (OD)/ ; },
abstract = {Strain diversity, while now recognized as a key driver underlying partner dynamics in symbioses, is usually difficult to experimentally manipulate and image in hosts with complex microbiota. To address this problem, we have used the luminous marine bacterium Vibrio fischeri, which establishes a symbiosis within the crypts of the nascent light organ of the squid Euprymna scolopes. Competition assays in newly hatched juvenile squid have shown that symbiotic V. fischeri are either niche-sharing "S strains", which share the light organ when co-inoculated with other S strains, or niche-dominant "D strains", which are typically found alone in the light organ after a co-colonization. To understand this D strain advantage, we determined the minimum time that different V. fischeri strains needed to initiate colonization and used confocal microscopy to localize the symbionts along their infection track. Further, we determined whether symbiont-induced host morphogenic events also occurred earlier during a D strain colonization. We conclude that D strains colonized more quickly than S strains. Nevertheless, light-organ populations in field-caught adult squid often contain both D and S strains. We determined experimentally that this symbiont population heterogeneity might be achieved in nature by a serial encounter of different strains in the environment.},
}
@article {pmid30320217,
year = {2018},
author = {Kremer, N and Koch, EJ and El Filali, A and Zhou, L and Heath-Heckman, EAC and Ruby, EG and McFall-Ngai, MJ},
title = {Persistent Interactions with Bacterial Symbionts Direct Mature-Host Cell Morphology and Gene Expression in the Squid-Vibrio Symbiosis.},
journal = {mSystems},
volume = {3},
number = {5},
pages = {},
doi = {10.1128/mSystems.00165-18},
pmid = {30320217},
issn = {2379-5077},
abstract = {In horizontally transmitted symbioses, structural, biochemical, and molecular features both facilitate host colonization by specific symbionts and mediate their persistent carriage. In the association between the squid Euprymna scolopes and its luminous bacterial partner Vibrio fischeri, the symbionts interact with two epithelial fields; they interact (i) transiently with the superficial ciliated field that potentiates colonization and regresses within days of colonization and (ii) persistently with the cells that line the internal crypts, whose ultrastructure changes in response to the symbionts. Development of the association creates conditions that promote the symbiotic partner over the lifetime of the host. To determine whether light organ maturation requires continuous interactions with V. fischeri or only the signaling that occurs during its initiation, we compared 4-week-old squid that were uncolonized with those colonized either persistently by wild-type V. fischeri or transiently by a V. fischeri mutant that triggers early events in morphogenesis but does not persist. Microscopic analysis of the light organs showed that, while morphogenesis of the superficial ciliated field is greatly accelerated by V. fischeri colonization, its eventual outcome is largely independent of colonization state. In contrast, the symbiont-induced changes in crypt cell shape require persistent host-symbiont interaction, reflected in the similarity between uncolonized and transiently colonized animals. Transcriptomic analyses reflected the microscopy results; host gene expression at 4 weeks was due primarily to the persistent interactions of host and symbiont cells. Further, the transcriptomic signature of specific pathways reflected the daily rhythm of symbiont release and regrowth and required the presence of the symbionts. IMPORTANCE A long-term relationship between symbiotic partners is often characterized by development and maturation of host structures that harbor the symbiont cells over the host's lifetime. To understand the mechanisms involved in symbiosis maintenance more fully, we studied the mature bobtail squid, whose light-emitting organ, under experimental conditions, can be transiently or persistently colonized by Vibrio fischeri or remain uncolonized. Superficial anatomical changes in the organ were largely independent of symbiosis. However, both the microanatomy of cells with which symbionts interact and the patterns of gene expression in the mature animal were due principally to the persistent interactions of host and symbiont cells rather than to a response to early colonization events. Further, the characteristic pronounced daily rhythm on the host transcriptome required persistent V. fischeri colonization of the organ. This experimental study provides a window into how persistent symbiotic colonization influences the form and function of host animal tissues.},
}
@article {pmid30299554,
year = {2018},
author = {Thompson, CM and Tischler, AH and Tarnowski, DA and Mandel, MJ and Visick, KL},
title = {Nitric oxide inhibits biofilm formation by Vibrio fischeri via the nitric oxide-sensor HnoX.},
journal = {Molecular microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/mmi.14147},
pmid = {30299554},
issn = {1365-2958},
abstract = {Nitric oxide (NO) is an important defense molecule secreted by the squid Euprymna scolopes and sensed by the bacterial symbiont, Vibrio fischeri, via the NO-sensor HnoX. HnoX inhibits colonization through an unknown mechanism. The genomic location of hnoX adjacent to hahK, a recently identified positive regulator of biofilm formation, suggested that HnoX may inhibit colonization by controlling biofilm formation, a key early step in colonization. Indeed, deletion of hnoX resulted in early biofilm formation in vitro, an effect that was dependent on HahK and its putative phosphotransfer residues. An allele of hnoX that encodes a protein with increased activity severely delayed wrinkled colony formation. Control occurred at the level of transcription of the syp genes, which produce the polysaccharide matrix component. The addition of NO abrogated biofilm formation and diminished syp transcription, effects that required HnoX. Finally, an hnoX mutant formed larger symbiotic biofilms. This work has thus uncovered a host-relevant signal controlling biofilms and a mechanism for inhibition of biofilm formation by V. fischeri. The study of V. fischeri HnoX permits us to understand not only host-associated biofilm mechanisms, but also the function of HnoX domain proteins as regulators of important bacterial processes. This article is protected by copyright. All rights reserved.},
}
@article {pmid30151160,
year = {2018},
author = {Coryell, RL and Turnham, KE and de Jesus Ayson, EG and Lavilla-Pltogo, C and Alcala, AC and Sotto, F and Gonzales, B and Nishiguchi, MK},
title = {Phylogeographic patterns in the Philippine archipelago influence symbiont diversity in the bobtail squid-Vibrio mutualism.},
journal = {Ecology and evolution},
volume = {8},
number = {15},
pages = {7421-7435},
doi = {10.1002/ece3.4266},
pmid = {30151160},
issn = {2045-7758},
abstract = {Marine microbes encounter a myriad of biotic and abiotic factors that can impact fitness by limiting their range and capacity to move between habitats. This is especially true for environmentally transmitted bacteria that cycle between their hosts and the surrounding habitat. As geologic history, biogeography, and other factors such as water temperature, salinity, and physical barriers can inhibit bacterial movement to novel environments, we chose to examine the genetic architecture of Euprymna albatrossae (Mollusca: Cephalopoda) and their Vibrio fischeri symbionts in the Philippine archipelago using a combined phylogeographic approach. Eleven separate sites in the Philippine islands were examined using haplotype estimates that were examined via nested clade analysis to determine the relationship between E. albatrossae and V. fischeri populations and their geographic location. Identical analyses of molecular variance (AMOVA) were used to estimate variation within and between populations for host and symbiont genetic data. Host animals demonstrated a significant amount of variation within island groups, while symbiont variation was found within individual populations. Nested clade phylogenetic analysis revealed that hosts and symbionts may have colonized this area at different times, with a sudden change in habitat. Additionally, host data indicate restricted gene flow, whereas symbionts show range expansion, followed by periodic restriction to genetic flow. These differences between host and symbiont networks indicate that factors "outside the squid" influence distribution of Philippine V. fischeri. Our results shed light on how geography and changing environmental factors can impact marine symbiotic associations at both local and global scales.},
}
@article {pmid30136358,
year = {2018},
author = {Koehler, S and Gaedeke, R and Thompson, C and Bongrand, C and Visick, K and Ruby, E and McFall-Ngai, M},
title = {The model squid-vibrio symbiosis provides a window into the impact of strain- and species-level differences during the initial stages of symbiont engagement.},
journal = {Environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1462-2920.14392},
pmid = {30136358},
issn = {1462-2920},
abstract = {Among horizontally acquired symbioses, the mechanisms underlying microbial strain- and species-level specificity remain poorly understood. Here, confocal-microscopy analyses and genetic manipulation of the squid-vibrio association revealed quantitative differences in a symbiont's capacity to interact with the host during initial engagement. Specifically, dominant strains of Vibrio fischeri, 'D-type', previously named for their dominant, single-strain colonization of the squid's bioluminescent organ, were compared with 'S-type', or 'sharing', strains, which can co-colonize the organ. These D-type strains typically: (i) formed aggregations of 100s-1000s of cells on the light-organ surface, up to 3 orders of magnitude larger than those of S-type strains; (ii) showed dominance in co-aggregation experiments, independent of inoculum size or strain proportion; (iii) perturbed larger areas of the organ's ciliated surface; and, (iv) appeared at the pore of the organ ~4Xs more quickly than S-type strains. At least in part, genes responsible for biofilm synthesis control the hyperaggregation phenotype of a D-type strain. Other marine vibrios produced relatively small aggregations, while an array of marine Gram-positive and -negative species outside of the Vibrionaceae did not attach to the organ's surface. These studies provide insight into the impact of strain variation on early events leading to establishment of an environmentally acquired symbiosis. This article is protected by copyright. All rights reserved.},
}
@article {pmid30127013,
year = {2018},
author = {Speare, L and Cecere, AG and Guckes, KR and Smith, S and Wollenberg, MS and Mandel, MJ and Miyashiro, T and Septer, AN},
title = {Bacterial symbionts use a type VI secretion system to eliminate competitors in their natural host.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {},
number = {},
pages = {},
doi = {10.1073/pnas.1808302115},
pmid = {30127013},
issn = {1091-6490},
abstract = {Intraspecific competition describes the negative interaction that occurs when different populations of the same species attempt to fill the same niche. Such competition is predicted to occur among host-associated bacteria but has been challenging to study in natural biological systems. Although many bioluminescent Vibrio fischeri strains exist in seawater, only a few strains are found in the light-organ crypts of an individual wild-caught Euprymna scolopes squid, suggesting a possible role for intraspecific competition during early colonization. Using a culture-based assay to investigate the interactions of different V. fischeri strains, we found "lethal" and "nonlethal" isolates that could kill or not kill the well-studied light-organ isolate ES114, respectively. The killing phenotype of these lethal strains required a type VI secretion system (T6SS) encoded in a 50-kb genomic island. Multiple lethal and nonlethal strains could be cultured from the light organs of individual wild-caught adult squid. Although lethal strains eliminate nonlethal strains in vitro, two lethal strains could coexist in interspersed microcolonies that formed in a T6SS-dependent manner. This coexistence was destabilized upon physical mixing, resulting in one lethal strain consistently eliminating the other. When juvenile squid were coinoculated with lethal and nonlethal strains, they occupied different crypts, yet they were observed to coexist within crypts when T6SS function was disrupted. These findings, using a combination of natural isolates and experimental approaches in vitro and in the animal host, reveal the importance of T6SS in spatially separating strains during the establishment of host colonization in a natural symbiosis.},
}
@article {pmid28401748,
year = {2017},
author = {Davidson, SK},
title = {The squid insurance plan: female Euprymna scolopes add potentially protective bacteria to the egg coats of their clutches.},
journal = {Environmental microbiology},
volume = {19},
number = {6},
pages = {2112-2114},
doi = {10.1111/1462-2920.13751},
pmid = {28401748},
issn = {1462-2920},
mesh = {Aliivibrio fischeri ; Animals ; Bacteria ; *Decapodiformes ; Female ; Humans ; Seafood ; *Symbiosis ; },
}
@article {pmid30048543, year = {2018}, author = {Reddi, G and Pruss, K and Cottingham, KL and Taylor, RK and Almagro-Moreno, S}, title = {Catabolism of mucus components influences motility of Vibrio cholerae in the presence of environmental reservoirs.}, journal = {PloS one}, volume = {13}, number = {7}, pages = {e0201383}, doi = {10.1371/journal.pone.0201383}, pmid = {30048543}, issn = {1932-6203}, abstract = {Vibrio cholerae O1, the etiological agent of cholera, is a natural inhabitant of aquatic ecosystems. Motility is a critical element for the colonization of both the human host and its environmental reservoirs. In this study, we investigated the molecular mechanisms underlying the chemotactic response of V. cholerae in the presence of some of its environmental reservoirs. We found that, from the several oligosaccharides found in mucin, two specifically triggered motility of V. cholerae O1: N-acetylneuraminic acid (Neu5Ac) and N-acetylglucosamine (GlcNAc). We determined that the compounds need to be internally catabolized in order to trigger motility of V. cholerae. Interestingly, the catabolism of Neu5Ac and GlcNAc converges and the production of one molecule common to both pathways, glucosamine-6-phosphate (GlcN-6P), is essential to induce motility in the presence of both compounds. Mutants unable to produce GlcN-6P show greatly reduced motility towards mucin. Furthermore, we determined that the production of GlcN-6P is necessary to induce motility of V. cholerae in the presence of some of its environmental reservoirs such as crustaceans or cyanobacteria, revealing a molecular link between the two distinct modes of the complex life cycle of V. cholerae. Finally, cross-species comparisons revealed varied chemotactic responses towards mucin, GlcNAc, and Neu5Ac for environmental (non-pathogenic) strains of V. cholerae, clinical and environmental isolates of the human pathogens Vibrio vulnificus and Vibrio parahaemolyticus, and fish and squid isolates of the symbiotic bacterium Vibrio fischeri. The data presented here suggest nuance in convergent strategies across species of the same bacterial family for motility towards suitable substrates for colonization.}, }
@article {pmid30048543,
year = {2018},
author = {Reddi, G and Pruss, K and Cottingham, KL and Taylor, RK and Almagro-Moreno, S},
title = {Catabolism of mucus components influences motility of Vibrio cholerae in the presence of environmental reservoirs.},
journal = {PloS one},
volume = {13},
number = {7},
pages = {e0201383},
doi = {10.1371/journal.pone.0201383},
pmid = {30048543},
issn = {1932-6203},
abstract = {Vibrio cholerae O1, the etiological agent of cholera, is a natural inhabitant of aquatic ecosystems. Motility is a critical element for the colonization of both the human host and its environmental reservoirs. In this study, we investigated the molecular mechanisms underlying the chemotactic response of V. cholerae in the presence of some of its environmental reservoirs. We found that, from the several oligosaccharides found in mucin, two specifically triggered motility of V. cholerae O1: N-acetylneuraminic acid (Neu5Ac) and N-acetylglucosamine (GlcNAc). We determined that the compounds need to be internally catabolized in order to trigger motility of V. cholerae. Interestingly, the catabolism of Neu5Ac and GlcNAc converges and the production of one molecule common to both pathways, glucosamine-6-phosphate (GlcN-6P), is essential to induce motility in the presence of both compounds. Mutants unable to produce GlcN-6P show greatly reduced motility towards mucin. Furthermore, we determined that the production of GlcN-6P is necessary to induce motility of V. cholerae in the presence of some of its environmental reservoirs such as crustaceans or cyanobacteria, revealing a molecular link between the two distinct modes of the complex life cycle of V. cholerae. Finally, cross-species comparisons revealed varied chemotactic responses towards mucin, GlcNAc, and Neu5Ac for environmental (non-pathogenic) strains of V. cholerae, clinical and environmental isolates of the human pathogens Vibrio vulnificus and Vibrio parahaemolyticus, and fish and squid isolates of the symbiotic bacterium Vibrio fischeri. The data presented here suggest nuance in convergent strategies across species of the same bacterial family for motility towards suitable substrates for colonization.},
}
@article {pmid30030225,
year = {2018},
author = {Thompson, CM and Marsden, AE and Tischler, AH and Koo, J and Visick, KL},
title = {A genetic analysis reveals that a trio of regulators prevents biofilm formation by Vibrio fischeri.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1128/AEM.01257-18},
pmid = {30030225},
issn = {1098-5336},
abstract = {Biofilms, complex communities of microorganisms surrounded by a self-produced matrix, facilitate attachment and provide protection to bacteria. A natural model used to study biofilm formation is the symbiosis between Vibrio fischeri and its host, the Hawaiian bobtail squid, Euprymna scolopes Host-relevant biofilm formation is a tightly regulated process and is only observed in vitro with strains that have been genetically manipulated to overexpress or disrupt specific regulators, primarily two-component signaling (TCS) regulators. These regulators control biofilm formation by dictating the production of the symbiosis polysaccharide (Syp-PS), the major component of the biofilm matrix. Control occurs both at and below the level of transcription of syp, the genes responsible for Syp-PS production. Here, we probed the roles of the two known negative regulators of biofilm formation, BinK and SypE, by generating double mutants. We also mapped and evaluated a point mutation using natural transformation and linkage analysis. We examined traditional biofilm formation phenotypes and established a new assay for evaluating the start of biofilm formation in the form of microscopic aggregates in shaking liquid cultures, in the absence of the known biofilm-inducing signal, calcium. We found that wrinkled colony formation is negatively controlled not only by BinK and SypE, but also by SypF. SypF is both required for and inhibitory to biofilm formation. Together, these data reveal that these three regulators are sufficient to prevent wild-type V. fischeri from forming biofilms under these conditions.Importance Bacterial biofilms promote attachment to a variety of surfaces and protect the constituent bacteria from environmental stresses, including antimicrobials. Understanding the mechanisms by which biofilms form will promote our ability to resolve them when they occur in the context of an infection. In this study, we found that Vibrio fischeri tightly controls biofilm formation using three negative regulators; the presence of a single one of these regulators was sufficient to prevent full biofilm development, while disruption of all three permitted robust biofilm formation. This work increases our understanding of the functions of specific regulators and demonstrates the substantial negative control that one benign microbe exerts over biofilm formation, potentially to ensure that it occurs only under the appropriate conditions.},
}
@article {pmid29946051,
year = {2018},
author = {Hendry, TA and Freed, LL and Fader, D and Fenolio, D and Sutton, TT and Lopez, JV},
title = {Ongoing Transposon-Mediated Genome Reduction in the Luminous Bacterial Symbionts of Deep-Sea Ceratioid Anglerfishes.},
journal = {mBio},
volume = {9},
number = {3},
pages = {},
doi = {10.1128/mBio.01033-18},
pmid = {29946051},
issn = {2150-7511},
abstract = {Diverse marine fish and squid form symbiotic associations with extracellular bioluminescent bacteria. These symbionts are typically free-living bacteria with large genomes, but one known lineage of symbionts has undergone genomic reduction and evolution of host dependence. It is not known why distinct evolutionary trajectories have occurred among different luminous symbionts, and not all known lineages previously had genome sequences available. In order to better understand patterns of evolution across diverse bioluminescent symbionts, we de novo sequenced the genomes of bacteria from a poorly studied interaction, the extracellular symbionts from the "lures" of deep-sea ceratioid anglerfishes. Deep-sea anglerfish symbiont genomes are reduced in size by about 50% compared to free-living relatives. They show a striking convergence of genome reduction and loss of metabolic capabilities with a distinct lineage of obligately host-dependent luminous symbionts. These losses include reductions in amino acid synthesis pathways and abilities to utilize diverse sugars. However, the symbiont genomes have retained a number of categories of genes predicted to be useful only outside the host, such as those involved in chemotaxis and motility, suggesting that they may persist in the environment. These genomes contain very high numbers of pseudogenes and show massive expansions of transposable elements, with transposases accounting for 28 and 31% of coding sequences in the symbiont genomes. Transposon expansions appear to have occurred at different times in each symbiont lineage, indicating either independent evolutions of reduction or symbiont replacement. These results suggest ongoing genomic reduction in extracellular luminous symbionts that is facilitated by transposon proliferations.IMPORTANCE Many female deep-sea anglerfishes possess a "lure" containing luminous bacterial symbionts. Here we show that unlike most luminous symbionts, these bacteria are undergoing an evolutionary transition toward small genomes with limited metabolic capabilities. Comparative analyses of the symbiont genomes indicate that this transition is ongoing and facilitated by transposon expansions. This transition may have occurred independently in different symbiont lineages, although it is unclear why. Genomic reduction is common in bacteria that only live within host cells but less common in bacteria that, like anglerfish symbionts, live outside host cells. Since multiple evolutions of genomic reduction have occurred convergently in luminous bacteria, they make a useful system with which to understand patterns of genome evolution in extracellular symbionts. This work demonstrates that ecological factors other than an intracellular lifestyle can lead to dramatic gene loss and evolutionary changes and that transposon expansions may play important roles in this process.},
}
@article {pmid29752265,
year = {2018},
author = {Stoudenmire, JL and Essock-Burns, T and Weathers, EN and Solaimanpour, S and Mrázek, J and Stabb, EV},
title = {An iterative synthetic approach to engineer a high-performing PhoB-specific reporter.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1128/AEM.00603-18},
pmid = {29752265},
issn = {1098-5336},
abstract = {Transcriptional reporters are common tools for analyzing either the transcription of a gene of interest or the activity of a specific transcriptional regulator. Unfortunately, the latter application has the shortcoming that native promoters did not evolve as optimal readouts for the activity of a particular regulator. We sought to synthesize an optimized transcriptional reporter for assessing PhoB activity, aiming for maximal "on" expression when PhoB is active, minimal background in the "off" state, and no control elements for other regulators. We designed specific sequences for promoter elements with appropriately spaced PhoB-binding sites, and at nineteen additional intervening nucleotide positions for which we did not predict sequence-specific effects the bases were randomized. Eighty-three such constructs were screened in Vibrio fischeri, enabling us to identify bases at particular randomized positions that significantly correlated with high "on" or low "off" expression. A second round of promoter design rationally constrained thirteen additional positions, leading to a reporter with high PhoB-dependent expression, essentially no background, and no other known regulatory elements. As expressed reporters, we used both stable and destabilized GFP, the latter with a half-life of eighty-one minutes in V. fischeri In culture, PhoB induced the reporter when phosphate was depleted below 10 μM. During symbiotic colonization of its host squid Euprymna scolopes, the reporter indicated heterogeneous phosphate availability in different light-organ microenvironments. Finally, testing this construct in other Proteobacteria demonstrated its broader utility. The results illustrate how a limited ability to predict synthetic promoter-reporter performance can be overcome through iterative screening and re-engineering.IMPORTANCE Transcriptional reporters can be powerful tools for assessing when a particular regulator is active; however, native promoters may not be ideal for this purpose. Optimal reporters should be specific to the regulator being examined and should maximize the difference between "on" and "off" states; however, these properties are distinct from the selective pressures driving the evolution of natural promoters. Synthetic promoters offer a promising alternative, but our understanding often does not enable fully predictive promoter design, and the large number of alternative sequence possibilities can be intractable. In a synthetic promoter region with over thirty-four billion sequence variants, we identified bases correlated with favorable performance by screening only eighty-three candidates, allowing us to rationally constrain our design. We thereby generated an optimized reporter that is induced by PhoB and used it to explore the low-phosphate response of V. fischeri This promoter-design strategy will facilitate the engineering of other regulator-specific reporters.},
}
@article {pmid29692003,
year = {2018},
author = {Peyer, SM and Kremer, N and McFall-Ngai, MJ},
title = {Involvement of a host Cathepsin L in symbiont-induced cell death.},
journal = {MicrobiologyOpen},
volume = {},
number = {},
pages = {e00632},
doi = {10.1002/mbo3.632},
pmid = {29692003},
issn = {2045-8827},
abstract = {The cathepsin L gene of the host squid, Euprymna scolopes, is upregulated during the first hours of colonization by the symbiont Vibrio fischeri. At this time, the symbiotic organ begins cell death-mediated morphogenesis in tissues functional only at the onset of symbiosis. The goal of this study was to determine whether Cathepsin L, a cysteine protease associated with apoptosis in other animals, plays a critical role in symbiont-induced cell death in the host squid. Sequence analysis and biochemical characterization demonstrated that the protein has key residues and domains essential for Cathepsin L function and that it is active within the pH range typical of these proteases. With in situ hybridization and immunocytochemistry, we localized the transcript and protein, respectively, to cells interacting with V. fischeri. Activity of the protein occurred along the path of symbiont colonization. A specific Cathepsin L, nonspecific cysteine protease, and caspase inhibitor each independently attenuated activity and cell death to varying degrees. In addition, a specific antibody decreased cell death by ~50%. Together these data provide evidence that Cathepsin L is a critical component in the symbiont-induced cell death that transforms the host tissues from a colonization morphology to one that promotes the mature association.},
}
@article {pmid29651249,
year = {2018},
author = {Seehafer, K and Brophy, S and Tom, SR and Crook, RJ},
title = {Ontogenetic and Experience-Dependent Changes in Defensive Behavior in Captive-Bred Hawaiian Bobtail Squid, Euprymna scolopes.},
journal = {Frontiers in physiology},
volume = {9},
number = {},
pages = {299},
doi = {10.3389/fphys.2018.00299},
pmid = {29651249},
issn = {1664-042X},
abstract = {Cephalopod molluscs are known for their extensive behavioral repertoire and their impressive learning abilities. Their primary defensive behaviors, such as camouflage, have received detailed study, but knowledge is limited to intensive study of relatively few species. A considerable challenge facing cephalopod research is the need to establish new models that can be captive bred, are tractable for range of different experimental procedures, and that will address broad questions in biological research. The Hawaiian Bobtail Squid (Euprymna scolopes) is a small, tropical cephalopod that has a long history of research in the field of microbial symbiosis, but offers great promise as a novel behavioral and neurobiological model. It can be bred in the laboratory through multiple generations, one of the few species of cephalopod that can meet this requirement (which is incorporated in regulations such as EU directive 2010/63/EU). Additionally, laboratory culture makes E. scolopes an ideal model for studying ontogeny- and experience-dependent behaviors. In this study, we show that captive bred juvenile and adult E. scolopes produce robust, repeatable defensive behaviors when placed in an exposed environment and presented with a visual threat. Further, adult and juvenile squid employ different innate defensive behaviors when presented with a size-matched model predator. When a 10-min training procedure was repeated over three consecutive days, defensive behaviors habituated in juvenile squid for at least 5 days after training, but memory did not appear to persist for 14 days. In contrast, adult squid did not show any evidence of long-term habituation memory. Thus we conclude that this species produces a range of quantifiable, modifiable behaviors even in a laboratory environment where ecologically-relevant, complex behavioral sequences may not reliably occur. We suggest that the lack of long-term memory in adult squid may be related to their less escalated initial response to the mimic, and thus indicates less motivation to retain memory and not necessary inability to form memory. This is the first demonstration of age-related differences in defensive behaviors in Euprymna, and the first record of habituation in this experimentally tractable genus of squid.},
}
@article {pmid29600280,
year = {2018},
author = {Kerwin, AH and Nyholm, SV},
title = {Reproductive System Symbiotic Bacteria Are Conserved between Two Distinct Populations of Euprymna scolopes from Oahu, Hawaii.},
journal = {mSphere},
volume = {3},
number = {2},
pages = {},
doi = {10.1128/mSphere.00531-17},
pmid = {29600280},
issn = {2379-5042},
abstract = {Female Hawaiian bobtail squid, Euprymna scolopes, harbor a symbiotic bacterial community in a reproductive organ, the accessory nidamental gland (ANG). This community is known to be stable over several generations of wild-caught bobtail squid but has, to date, been examined for only one population in Maunalua Bay, Oahu, HI. This study assessed the ANG and corresponding egg jelly coat (JC) bacterial communities for another genetically isolated host population from Kaneohe Bay, Oahu, HI, using 16S amplicon sequencing. The bacterial communities from the ANGs and JCs of the two populations were found to be similar in richness, evenness, phylogenetic diversity, and overall community composition. However, the Kaneohe Bay samples formed their own subset within the Maunalua Bay ANG/JC community. An Alteromonadaceae genus, BD2-13, was significantly higher in relative abundance in the Kaneohe Bay population, and several Alphaproteobacteria taxa also shifted in relative abundance between the two groups. This variation could be due to local adaptation to differing environmental challenges, to localized variability, or to functional redundancy among the ANG taxa. The overall stability of the community between the populations further supports a crucial functional role that has been hypothesized for this symbiosis. IMPORTANCE In this study, we examined the reproductive ANG symbiosis found in two genetically isolated populations of the Hawaiian bobtail squid, Euprymna scolopes. The stability of the community reported here provides support for the hypothesis that this symbiosis is under strong selective pressure, while the observed differences suggest that some level of local adaptation may have occurred. These two host populations are frequently used interchangeably as source populations for research. Euprymna scolopes is an important model organism and offers the opportunity to examine the interplay between a binary and a consortial symbiosis in a single model host. Understanding the inherent natural variability of this association will aid in our understanding of the conservation, function, transmission, and development of the ANG symbiosis.},
}
@article {pmid29463601,
year = {2018},
author = {Tischler, AH and Lie, L and Thompson, CM and Visick, KL},
title = {Discovery of Calcium as a Biofilm-Promoting Signal for Vibrio fischeri Reveals New Phenotypes and Underlying Regulatory Complexity.},
journal = {Journal of bacteriology},
volume = {200},
number = {15},
pages = {},
doi = {10.1128/JB.00016-18},
pmid = {29463601},
issn = {1098-5530},
support = {R01 GM114288/GM/NIGMS NIH HHS/United States ; },
abstract = {Vibrio fischeri uses biofilm formation to promote symbiotic colonization of its squid host, Euprymna scolopes Control over biofilm formation is exerted at the level of transcription of the symbiosis polysaccharide (syp) locus by a complex set of two-component regulators. Biofilm formation can be induced by overproduction of the sensor kinase RscS, which requires the activities of the hybrid sensor kinase SypF and the response regulator SypG and is negatively regulated by the sensor kinase BinK. Here, we identify calcium as a signal that promotes biofilm formation by biofilm-competent strains under conditions in which biofilms are not typically observed (growth with shaking). This was true for RscS-overproducing cells as well as for strains in which only the negative regulator binK was deleted. The latter results provided, for the first time, an opportunity to induce and evaluate biofilm formation without regulator overexpression. Using these conditions, we determined that calcium induces both syp-dependent and bacterial cellulose synthesis (bcs)-dependent biofilms at the level of transcription of these loci. The calcium-induced biofilms were dependent on SypF, but SypF's Hpt domain was sufficient for biofilm formation. These data suggested the involvement of another sensor kinase(s) and led to the discovery that both RscS and a previously uncharacterized sensor kinase, HahK, functioned in this pathway. Together, the data presented here reveal both a new signal and biofilm phenotype produced by V. fischeri cells, the coordinate production of two polysaccharides involved in distinct biofilm behaviors, and a new regulator that contributes to control over these processes.IMPORTANCE Biofilms, or communities of surface-attached microorganisms adherent via a matrix that typically includes polysaccharides, are highly resistant to environmental stresses and are thus problematic in the clinic and important to study. Vibrio fischeri forms biofilms to colonize its symbiotic host, making this organism useful for studying biofilms. Biofilm formation depends on the syp polysaccharide locus and its regulators. Here, we identify a signal, calcium, that induces both SYP-PS and cellulose-dependent biofilms. We also identify a new syp regulator, the sensor kinase HahK, and discover a mutant phenotype for the sensor kinase RscS. This work thus reveals a specific biofilm-inducing signal that coordinately controls two polysaccharides, identifies a new regulator, and clarifies the regulatory control over biofilm formation by V. fischeri.},
}
@article {pmid29269839,
year = {2018},
author = {Kinosita, Y and Kikuchi, Y and Mikami, N and Nakane, D and Nishizaka, T},
title = {Unforeseen swimming and gliding mode of an insect gut symbiont, Burkholderia sp. RPE64, with wrapping of the flagella around its cell body.},
journal = {The ISME journal},
volume = {12},
number = {3},
pages = {838-848},
doi = {10.1038/s41396-017-0010-z},
pmid = {29269839},
issn = {1751-7370},
abstract = {A bean bug symbiont, Burkholderia sp. RPE64, selectively colonizes the gut crypts by flagella-mediated motility: however, the mechanism for this colonization remains unclear. Here, to obtain clues to this mechanism, we characterized the swimming motility of the Burkholderia symbiont under an advanced optical microscope. High-speed imaging of cells enabled the detection of turn events with up to 5-ms temporal resolution, indicating that cells showed reversal motions (θ ~ 180°) with rapid changes in speed by a factor of 3.6. Remarkably, staining of the flagellar filaments with a fluorescent dye Cy3 revealed that the flagellar filaments wrap around the cell body with a motion like that of a ribbon streamer in rhythmic gymnastics. A motility assay with total internal reflection fluorescence microscopy revealed that the left-handed flagellum wound around the cell body and propelled it forward by its clockwise rotation. We also detected periodic-fluorescent signals of flagella on the glass surface, suggesting that flagella possibly contacted the solid surface directly and produced a gliding-like motion driven by flagellar rotation. Finally, the wrapping motion was also observed in a symbiotic bacterium of the bobtail squid, Aliivibrio fischeri, suggesting that this motility mode may contribute to migration on the mucus-filled narrow passage connecting to the symbiotic organ.},
}
@article {pmid28898600,
year = {2017},
author = {Zepeda, EA and Veline, RJ and Crook, RJ},
title = {Rapid Associative Learning and Stable Long-Term Memory in the Squid Euprymna scolopes.},
journal = {The Biological bulletin},
volume = {232},
number = {3},
pages = {212-218},
doi = {10.1086/693461},
pmid = {28898600},
issn = {1939-8697},
mesh = {Animals ; Decapodiformes/*physiology ; Learning/physiology ; Memory/*physiology ; Predatory Behavior/physiology ; },
abstract = {Learning and memory in cephalopod molluscs have received intensive study because of cephalopods' complex behavioral repertoire and relatively accessible nervous systems. While most of this research has been conducted using octopus and cuttlefish species, there has been relatively little work on squid. Euprymna scolopes Berry, 1913, a sepiolid squid, is a promising model for further exploration of cephalopod cognition. These small squid have been studied in detail for their symbiotic relationship with bioluminescent bacteria, and their short generation time and successful captive breeding through multiple generations make them appealing models for neurobiological research. However, little is known about their behavior or cognitive ability. Using the well-established "prawn-in-the-tube" assay of learning and memory, we show that within a single 10-min trial E. scolopes learns to inhibit its predatory behavior, and after three trials it can retain this memory for at least 12 d. Rapid learning and very long-term retention were apparent under two different training schedules. To our knowledge, this study is the first demonstration of learning and memory in this species as well as the first demonstration of associative learning in any squid.},
}
@article {pmid28889973,
year = {2017},
author = {Guan, Z and Cai, T and Liu, Z and Dou, Y and Hu, X and Zhang, P and Sun, X and Li, H and Kuang, Y and Zhai, Q and Ruan, H and Li, X and Li, Z and Zhu, Q and Mai, J and Wang, Q and Lai, L and Ji, J and Liu, H and Xia, B and Jiang, T and Luo, SJ and Wang, HW and Xie, C},
title = {Origin of the Reflectin Gene and Hierarchical Assembly of Its Protein.},
journal = {Current biology : CB},
volume = {27},
number = {18},
pages = {2833-2842.e6},
doi = {10.1016/j.cub.2017.07.061},
pmid = {28889973},
issn = {1879-0445},
abstract = {Cephalopods, the group of animals including octopus, squid, and cuttlefish, have remarkable ability to instantly modulate body coloration and patterns so as to blend into surrounding environments [1, 2] or send warning signals to other animals [3]. Reflectin is expressed exclusively in cephalopods, filling the lamellae of intracellular Bragg reflectors that exhibit dynamic iridescence and structural color change [4]. Here, we trace the possible origin of the reflectin gene back to a transposon from the symbiotic bioluminescent bacterium Vibrio fischeri and report the hierarchical structural architecture of reflectin protein. Intrinsic self-assembly, and higher-order assembly tightly modulated by aromatic compounds, provide insights into the formation of multilayer reflectors in iridophores and spherical microparticles in leucophores and may form the basis of structural color change in cephalopods. Self-assembly and higher-order assembly in reflectin originated from a core repeating octapeptide (here named protopeptide), which may be from the same symbiotic bacteria. The origin of the reflectin gene and assembly features of reflectin protein are of considerable biological interest. The hierarchical structural architecture of reflectin and its domain and protopeptide not only provide insights for bioinspired photonic materials but also serve as unique "assembly tags" and feasible molecular platforms in biotechnology.},
}
@article {pmid28835539,
year = {2017},
author = {Nawroth, JC and Guo, H and Koch, E and Heath-Heckman, EAC and Hermanson, JC and Ruby, EG and Dabiri, JO and Kanso, E and McFall-Ngai, M},
title = {Motile cilia create fluid-mechanical microhabitats for the active recruitment of the host microbiome.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {114},
number = {36},
pages = {9510-9516},
doi = {10.1073/pnas.1706926114},
pmid = {28835539},
issn = {1091-6490},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*physiology ; Animals ; Cilia ; Decapodiformes/cytology/*microbiology ; Epithelium/ultrastructure ; Microbiota ; Microscopy, Video ; Mucus ; Sense Organs/*cytology/microbiology ; Symbiosis ; },
abstract = {We show that mucociliary membranes of animal epithelia can create fluid-mechanical microenvironments for the active recruitment of the specific microbiome of the host. In terrestrial vertebrates, these tissues are typically colonized by complex consortia and are inaccessible to observation. Such tissues can be directly examined in aquatic animals, providing valuable opportunities for the analysis of mucociliary activity in relation to bacteria recruitment. Using the squid-vibrio model system, we provide a characterization of the initial engagement of microbial symbionts along ciliated tissues. Specifically, we developed an empirical and theoretical framework to conduct a census of ciliated cell types, create structural maps, and resolve the spatiotemporal flow dynamics. Our multiscale analyses revealed two distinct, highly organized populations of cilia on the host tissues. An array of long cilia ([Formula: see text]25 [Formula: see text]m) with metachronal beat creates a flow that focuses bacteria-sized particles, at the exclusion of larger particles, into sheltered zones; there, a field of randomly beating short cilia ([Formula: see text]10 [Formula: see text]m) mixes the local fluid environment, which contains host biochemical signals known to prime symbionts for colonization. This cilia-mediated process represents a previously unrecognized mechanism for symbiont recruitment. Each mucociliary surface that recruits a microbiome such as the case described here is likely to have system-specific features. However, all mucociliary surfaces are subject to the same physical and biological constraints that are imposed by the fluid environment and the evolutionary conserved structure of cilia. As such, our study promises to provide insight into universal mechanisms that drive the recruitment of symbiotic partners.},
}
@article {pmid28830998,
year = {2017},
author = {Viegas, J},
title = {Profile of Margaret J. McFall-Ngai.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {114},
number = {36},
pages = {9494-9496},
doi = {10.1073/pnas.1713158114},
pmid = {28830998},
issn = {1091-6490},
mesh = {Animals ; Aquatic Organisms ; California ; Circadian Rhythm ; Decapodiformes/microbiology/physiology ; Female ; Hawaii ; History, 20th Century ; History, 21st Century ; Humans ; Microbiology/*history ; Symbiosis ; },
}
@article {pmid28619362,
year = {2017},
author = {Song, W and Mu, C and Li, R and Wang, C},
title = {Peroxiredoxin 1 from cuttlefish (Sepiella maindroni): Molecular characterization of development and its immune response against Vibrio alginolyticus.},
journal = {Fish & shellfish immunology},
volume = {67},
number = {},
pages = {596-603},
doi = {10.1016/j.fsi.2017.06.034},
pmid = {28619362},
issn = {1095-9947},
mesh = {Amino Acid Sequence ; Animals ; Base Sequence ; Decapodiformes/*genetics/*immunology ; *Immunity, Innate ; Peroxiredoxins/chemistry/*genetics/*immunology ; Phylogeny ; Random Allocation ; Sequence Alignment ; Vibrio alginolyticus/*physiology ; },
abstract = {The aim of this work was constructive to understand the function of peroxiredoxin (PRDX) family member Peroxiredoxin 1 in Sepiella maindroni (SmPrx1) through molecular mechanisms of reproduction, embryonic development and immune responses to Vibrio alginolyticus. The full-length cDNA of SmPrx1 was of 1062 bp, contains a 5' untranslated region (UTR) of 79bp, a 3' UTR of 359 bp, an open reading frame of 624 bp encoding 207 amino acids. The conserved peroxidase catalytic center "FYPLDFTFVCPTEI" and "GEVCPA" were observed in the sequence of SmPrx1; this indicated that it was a member of 2-Cys Prx. Quantitative real-time (qRT)-PCR assays revealed that SmPrx1 was ubiquitously expressed in all examined tissues, muscle, ink sac, liver, ovary, testis, intestine, gill and totally blood cells, and showed high levels in testis. SmPrx1 mRNA was ubiquitously detected in all tested tissues, and the expression was comparatively high in testis, hemocyte, liver and ovary. Moreover, the SmPrx1 gene transcript was detected at all five stages of embryonic development phases that were respectively the zygote stage, the pre-embryonic stage, the organogenesis stage, the morphological integrity stage, the pre-hatching stage. The general tendency of expression was gradually increased and rapidly decreased. High expressed in progenitive tissues and embryonic development exhibit the proliferation-associated protein characterization like in mammal. The expression levels of SmPrx1 in liver and hemocytes grew swiftly and quickly reached peak value after Vibrio alginolyticus challenge. As hours passed by, the expression level began to reduce and resumed to normal levels after 48 h. The antioxidant activity and peroxidase activity of SmPrx1 were 6.17 U/mg. The results showed that the recombined protein of SmPrx1 had antioxidant activity and was the importance part of the antioxidant system in Sepiella maindroni. This study provides useful information to help further understand the functional mechanism of Prx 1 in marine cephalopod immunity.},
}
@article {pmid28602684,
year = {2017},
author = {Li, R and Xu, Z and Mu, C and Song, W and Wang, C},
title = {Molecular cloning and characterization of a hemocyanin from Sepiella maindroni.},
journal = {Fish & shellfish immunology},
volume = {67},
number = {},
pages = {228-243},
doi = {10.1016/j.fsi.2017.06.009},
pmid = {28602684},
issn = {1095-9947},
mesh = {Amino Acid Sequence ; Anaerobiosis ; Animals ; Base Sequence ; Cloning, Molecular ; DNA, Complementary/genetics ; Decapodiformes/*genetics/*immunology ; Gene Expression Regulation/*immunology ; Hemocyanins/chemistry/*genetics/*immunology ; Immunity, Innate/*genetics ; Phylogeny ; RNA, Messenger/genetics ; Real-Time Polymerase Chain Reaction ; Sequence Alignment/veterinary ; Stress, Physiological ; Vibrio alginolyticus ; },
abstract = {Hemocyanins are respiratory proteins occurring freely dissolved in the hemolymph of many arthropods and molluscs. Hemocyanin and hemocyanin-derived peptides have been linked to key aspects of innate immunity. In the present study, the full-length cDNA encoding hemocyanin in Sepiella maindroni (SmHc) was cloned and characterized. Bioinformatic analysis predicted that SmHc contains one open reading frame of 10,032 bp and encodes a polypeptide of 3343 amino acids. Sequence analysis showed that the predicted protein sequence of SmHc contained eight functional units (FUs). Phylogenic analysis revealed that SmHc clustered with the mollusc Hcs. Quantitative real-time PCR assay detected SmHc transcripts were in a wide range of tissues, but mainly distributed in gills. After hypoxia or bacterial challenge, the expression level of SmHc in the gills was significantly higher than that of the control group. These results suggested that SmHc might play important roles in oxygen transport and the modulation of immune response in S. maindroni.},
}
@article {pmid28447935,
year = {2017},
author = {Sabrina Pankey, M and Foxall, RL and Ster, IM and Perry, LA and Schuster, BM and Donner, RA and Coyle, M and Cooper, VS and Whistler, CA},
title = {Host-selected mutations converging on a global regulator drive an adaptive leap towards symbiosis in bacteria.},
journal = {eLife},
volume = {6},
number = {},
pages = {},
doi = {10.7554/eLife.24414},
pmid = {28447935},
issn = {2050-084X},
mesh = {Adaptation, Biological ; Aliivibrio fischeri/enzymology/*genetics/*physiology ; Animal Structures/microbiology ; Animals ; Decapodiformes/*microbiology/physiology ; Gene Expression Regulation, Bacterial ; Immune Evasion ; *Mutation ; Protein Kinases/*genetics ; Quorum Sensing ; *Selection, Genetic ; *Symbiosis ; },
abstract = {Host immune and physical barriers protect against pathogens but also impede the establishment of essential symbiotic partnerships. To reveal mechanisms by which beneficial organisms adapt to circumvent host defenses, we experimentally evolved ecologically distinct bioluminescent Vibrio fischeri by colonization and growth within the light organs of the squid Euprymna scolopes. Serial squid passaging of bacteria produced eight distinct mutations in the binK sensor kinase gene, which conferred an exceptional selective advantage that could be demonstrated through both empirical and theoretical analysis. Squid-adaptive binK alleles promoted colonization and immune evasion that were mediated by cell-associated matrices including symbiotic polysaccharide (Syp) and cellulose. binK variation also altered quorum sensing, raising the threshold for luminescence induction. Preexisting coordinated regulation of symbiosis traits by BinK presented an efficient solution where altered BinK function was the key to unlock multiple colonization barriers. These results identify a genetic basis for microbial adaptability and underscore the importance of hosts as selective agents that shape emergent symbiont populations.},
}
@article {pmid28446608,
year = {2017},
author = {Pan, S and Nikolakakis, K and Adamczyk, PA and Pan, M and Ruby, EG and Reed, JL},
title = {Model-enabled gene search (MEGS) allows fast and direct discovery of enzymatic and transport gene functions in the marine bacterium Vibrio fischeri.},
journal = {The Journal of biological chemistry},
volume = {292},
number = {24},
pages = {10250-10261},
doi = {10.1074/jbc.M116.763193},
pmid = {28446608},
issn = {1083-351X},
support = {F32 GM112214/GM/NIGMS NIH HHS/United States ; R01 AI050661/AI/NIAID NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*genetics/growth & development/metabolism ; Animals ; Aquaculture ; Aquatic Organisms/*genetics/metabolism ; Bacterial Proteins/*genetics/metabolism ; Computer Simulation ; Decapodiformes/growth & development/microbiology ; Escherichia coli/genetics/growth & development/metabolism ; *Expert Systems ; Gene Deletion ; Genetic Complementation Test ; Genomic Library ; Genomics/*methods ; Hawaii ; High-Throughput Nucleotide Sequencing ; *Models, Genetic ; Molecular Sequence Annotation ; Open Reading Frames ; Pacific Ocean ; Recombinant Proteins/metabolism ; Reproducibility of Results ; Species Specificity ; },
abstract = {Whereas genomes can be rapidly sequenced, the functions of many genes are incompletely or erroneously annotated because of a lack of experimental evidence or prior functional knowledge in sequence databases. To address this weakness, we describe here a model-enabled gene search (MEGS) approach that (i) identifies metabolic functions either missing from an organism's genome annotation or incorrectly assigned to an ORF by using discrepancies between metabolic model predictions and experimental culturing data; (ii) designs functional selection experiments for these specific metabolic functions; and (iii) selects a candidate gene(s) responsible for these functions from a genomic library and directly interrogates this gene's function experimentally. To discover gene functions, MEGS uses genomic functional selections instead of relying on correlations across large experimental datasets or sequence similarity as do other approaches. When applied to the bioluminescent marine bacterium Vibrio fischeri, MEGS successfully identified five genes that are responsible for four metabolic and transport reactions whose absence from a draft metabolic model of V. fischeri caused inaccurate modeling of high-throughput experimental data. This work demonstrates that MEGS provides a rapid and efficient integrated computational and experimental approach for annotating metabolic genes, including those that have previously been uncharacterized or misannotated.},
}
@article {pmid28393904,
year = {2017},
author = {Casaburi, G and Goncharenko-Foster, I and Duscher, AA and Foster, JS},
title = {Transcriptomic changes in an animal-bacterial symbiosis under modeled microgravity conditions.},
journal = {Scientific reports},
volume = {7},
number = {},
pages = {46318},
doi = {10.1038/srep46318},
pmid = {28393904},
issn = {2045-2322},
abstract = {Spaceflight imposes numerous adaptive challenges for terrestrial life. The reduction in gravity, or microgravity, represents a novel environment that can disrupt homeostasis of many physiological processes. Additionally, it is becoming increasingly clear that an organism's microbiome is critical for host health and examining its resiliency in microgravity represents a new frontier for space biology research. In this study, we examine the impact of microgravity on the interactions between the squid Euprymna scolopes and its beneficial symbiont Vibrio fischeri, which form a highly specific binary mutualism. First, animals inoculated with V. fischeri aboard the space shuttle showed effective colonization of the host light organ, the site of the symbiosis, during space flight. Second, RNA-Seq analysis of squid exposed to modeled microgravity conditions exhibited extensive differential gene expression in the presence and absence of the symbiotic partner. Transcriptomic analyses revealed in the absence of the symbiont during modeled microgravity there was an enrichment of genes and pathways associated with the innate immune and oxidative stress response. The results suggest that V. fischeri may help modulate the host stress responses under modeled microgravity. This study provides a window into the adaptive responses that the host animal and its symbiont use during modeled microgravity.},
}
@article {pmid28377525,
year = {2017},
author = {Chen, F and Krasity, BC and Peyer, SM and Koehler, S and Ruby, EG and Zhang, X and McFall-Ngai, MJ},
title = {Bactericidal Permeability-Increasing Proteins Shape Host-Microbe Interactions.},
journal = {mBio},
volume = {8},
number = {2},
pages = {},
doi = {10.1128/mBio.00040-17},
pmid = {28377525},
issn = {2150-7511},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; T32 GM008692/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*growth & development/*immunology ; Animals ; Anti-Infective Agents/*metabolism ; Antimicrobial Cationic Peptides/*metabolism ; Blood Proteins/*metabolism ; Decapodiformes/*immunology/*microbiology ; *Symbiosis ; },
abstract = {We characterized bactericidal permeability-increasing proteins (BPIs) of the squid Euprymna scolopes, EsBPI2 and EsBPI4. They have molecular characteristics typical of other animal BPIs, are closely related to one another, and nest phylogenetically among invertebrate BPIs. Purified EsBPIs had antimicrobial activity against the squid's symbiont, Vibrio fischeri, which colonizes light organ crypt epithelia. Activity of both proteins was abrogated by heat treatment and coincubation with specific antibodies. Pretreatment under acidic conditions similar to those during symbiosis initiation rendered V. fischeri more resistant to the antimicrobial activity of the proteins. Immunocytochemistry localized EsBPIs to the symbiotic organ and other epithelial surfaces interacting with ambient seawater. The proteins differed in intracellular distribution. Further, whereas EsBPI4 was restricted to epithelia, EsBPI2 also occurred in blood and in a transient juvenile organ that mediates hatching. The data provide evidence that these BPIs play different defensive roles early in the life of E. scolopes, modulating interactions with the symbiont.IMPORTANCE This study describes new functions for bactericidal permeability-increasing proteins (BPIs), members of the lipopolysaccharide-binding protein (LBP)/BPI protein family. The data provide evidence that these proteins play a dual role in the modulation of symbiotic bacteria. In the squid-vibrio model, these proteins both control the symbiont populations in the light organ tissues where symbiont cells occur in dense monoculture and, concomitantly, inhibit the symbiont from colonizing other epithelial surfaces of the animal.},
}
@article {pmid28152560,
year = {2017},
author = {Thompson, LR and Nikolakakis, K and Pan, S and Reed, J and Knight, R and Ruby, EG},
title = {Transcriptional characterization of Vibrio fischeri during colonization of juvenile Euprymna scolopes.},
journal = {Environmental microbiology},
volume = {19},
number = {5},
pages = {1845-1856},
doi = {10.1111/1462-2920.13684},
pmid = {28152560},
issn = {1462-2920},
support = {F32 GM112214/GM/NIGMS NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*genetics/*metabolism ; Animals ; Decapodiformes/*microbiology ; Energy Metabolism/genetics ; RNA, Bacterial/genetics ; Signal Transduction ; Symbiosis/*physiology ; Transcriptome/genetics ; },
abstract = {The marine bacterium Vibrio fischeri is the monospecific symbiont of the Hawaiian bobtail squid, Euprymna scolopes, and the establishment of this association involves a number of signaling pathways and transcriptional responses between both partners. We report here the first full RNA-Seq dataset representing host-associated V. fischeri cells from colonized juvenile E. scolopes, as well as comparative transcriptomes under both laboratory and simulated marine planktonic conditions. These data elucidate the broad transcriptional changes that these bacteria undergo during the early stages of symbiotic colonization. We report several previously undescribed and unexpected transcriptional responses within the early stages of this symbiosis, including gene expression patterns consistent with biochemical stresses inside the host, and metabolic patterns distinct from those reported in associations with adult animals. Integration of these transcriptional data with a recently developed metabolic model of V. fischeri provides us with a clearer picture of the metabolic state of symbionts within the juvenile host, including their possible carbon sources. Taken together, these results expand our understanding of the early stages of the squid-vibrio symbiosis, and more generally inform the transcriptional responses underlying the activities of marine microbes during host colonization.},
}
@article {pmid28122010,
year = {2017},
author = {Marsden, AE and Grudzinski, K and Ondrey, JM and DeLoney-Marino, CR and Visick, KL},
title = {Impact of Salt and Nutrient Content on Biofilm Formation by Vibrio fischeri.},
journal = {PloS one},
volume = {12},
number = {1},
pages = {e0169521},
doi = {10.1371/journal.pone.0169521},
pmid = {28122010},
issn = {1932-6203},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; R01 GM114288/GM/NIGMS NIH HHS/United States ; },
mesh = {Agar ; Aliivibrio fischeri/*drug effects/growth & development ; Biofilms/*drug effects/growth & development ; Culture Media ; Sodium Chloride/*pharmacology ; },
abstract = {Vibrio fischeri, a marine bacterium and symbiont of the Hawaiian bobtail squid Euprymna scolopes, depends on biofilm formation for successful colonization of the squid's symbiotic light organ. Here, we investigated if culture conditions, such as nutrient and salt availability, affect biofilm formation by V. fischeri by testing the formation of wrinkled colonies on solid media. We found that V. fischeri forms colonies with more substantial wrinkling when grown on the nutrient-dense LBS medium containing NaCl relative to those formed on the more nutrient-poor, seawater-salt containing SWT medium. The presence of both tryptone and yeast extract was necessary for the production of "normal" wrinkled colonies; when grown on tryptone alone, the colonies displayed a divoting phenotype and were attached to the agar surface. We also found that the type and concentration of specific seawater salts influenced the timing of biofilm formation. Of the conditions assayed, wrinkled colony formation occurred earliest in LBS(-Tris) media containing 425 mM NaCl, 35 mM MgSO4, and 5 mM CaCl2. Pellicle formation, another measure of biofilm development, was also enhanced in these growth conditions. Therefore, both nutrient and salt availability contribute to V. fischeri biofilm formation. While growth was unaffected, these optimized conditions resulted in increased syp locus expression as measured by a PsypA-lacZ transcriptional reporter. We anticipate these studies will help us understand how the natural environment of V. fischeri affects its ability to form biofilms and, ultimately, colonize E. scolopes.},
}
@article {pmid28111565,
year = {2016},
author = {McAnulty, SJ and Nyholm, SV},
title = {The Role of Hemocytes in the Hawaiian Bobtail Squid, Euprymna scolopes: A Model Organism for Studying Beneficial Host-Microbe Interactions.},
journal = {Frontiers in microbiology},
volume = {7},
number = {},
pages = {2013},
doi = {10.3389/fmicb.2016.02013},
pmid = {28111565},
issn = {1664-302X},
abstract = {Most, if not all, animals engage in associations with bacterial symbionts. Understanding the mechanisms by which host immune systems and beneficial bacteria communicate is a fundamental question in the fields of immunology and symbiosis. The Hawaiian bobtail squid (Euprymna scolopes) engages in two known symbioses; a binary relationship with the light organ symbiont Vibrio fischeri, and a bacterial consortium within a specialized organ of the female reproductive system, the accessory nidamental gland (ANG). E. scolopes has a well-developed circulatory system that allows immune cells (hemocytes) to migrate into tissues, including the light organ and ANG. In the association with V. fischeri, hemocytes are thought to have a number of roles in the management of symbiosis, including the recognition of non-symbiotic bacteria and the contribution of chitin as a nutrient source for V. fischeri. Hemocytes are hypothesized to recognize bacteria through interactions between pattern recognition receptors and microbe-associated molecular patterns. Colonization by V. fischeri has been shown to affect the bacteria-binding behavior, gene expression, and proteome of hemocytes, indicating that the symbiont can modulate host immune function. In the ANG, hemocytes have also been observed interacting with the residing bacterial community. As a model host, E. scolopes offers a unique opportunity to study how the innate immune system interacts with both a binary and consortial symbiosis. This mini review will recapitulate what is known about the role of hemocytes in the light organ association and offer future directions for understanding how these immune cells interact with multiple types of symbioses.},
}
@article {pmid28105525,
year = {2017},
author = {Peyer, SM and Heath-Heckman, EAC and McFall-Ngai, MJ},
title = {Characterization of the cell polarity gene crumbs during the early development and maintenance of the squid-vibrio light organ symbiosis.},
journal = {Development genes and evolution},
volume = {227},
number = {6},
pages = {375-387},
doi = {10.1007/s00427-017-0576-5},
pmid = {28105525},
issn = {1432-041X},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; IOS 0817232//National Science Foundation/International ; T32 GM007215/GM/NIGMS NIH HHS/United States ; NRSA T-32 GM07215//Foundation for the National Institutes of Health/International ; RO1-A150661//Foundation for the National Institutes of Health/International ; RO1-OD11024//Foundation for the National Institutes of Health/International ; R01 OD011024/OD/NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Amino Acid Sequence ; Animals ; Apoptosis ; Cell Polarity ; Decapodiformes/anatomy & histology/cytology/*microbiology/*physiology ; Epithelial Cells/cytology/microbiology ; Eye/microbiology ; Gene Expression ; Membrane Proteins/chemistry/genetics/*metabolism ; *Symbiosis ; },
abstract = {The protein Crumbs is a determinant of apical-basal cell polarity and plays a role in apoptosis of epithelial cells and their protection against photodamage. Using the squid-vibrio system, a model for development of symbiotic partnerships, we examined the modulation of the crumbs gene in host epithelial tissues during initiation and maintenance of the association. The extracellular luminous symbiont Vibrio fischeri colonizes the apical surfaces of polarized epithelia in deep crypts of the Euprymna scolopes light organ. During initial colonization each generation, symbiont harvesting is potentiated by the biochemical and biophysical activity of superficial ciliated epithelia, which are several cell layers from the crypt epithelia where the symbionts reside. Within hours of crypt colonization, the symbionts induce the cell death mediated regression of the remote superficial ciliated fields. However, the crypt cells directly interacting with the symbiont are protected from death. In the squid host, we characterized the gene and encoded protein during light organ morphogenesis and in response to symbiosis. Features of the protein sequence and structure, phylogenetic relationships, and localization patterns in the eye supported assignment of the squid protein to the Crumbs family. In situ hybridization revealed that the crumbs transcript shows opposite expression at the onset of symbiosis in the two different regions of the light organ: elevated levels in the superficial epithelia were attenuated whereas low levels in the crypt epithelia were turned up. Although a rhythmic association in which the host controls the symbiont population over the day-night cycle begins in the juvenile upon colonization, cycling of crumbs was evident only in the adult organ with peak expression coincident with maximum symbiont population and luminescence. Our results provide evidence that crumbs responds to symbiont cues that induce developmental apoptosis and to symbiont population dynamics correlating with luminescence-based stress throughout the duration of the host-microbe association.},
}
@article {pmid28063183,
year = {2017},
author = {Kerwin, AH and Nyholm, SV},
title = {Symbiotic bacteria associated with a bobtail squid reproductive system are detectable in the environment, and stable in the host and developing eggs.},
journal = {Environmental microbiology},
volume = {19},
number = {4},
pages = {1463-1475},
doi = {10.1111/1462-2920.13665},
pmid = {28063183},
issn = {1462-2920},
mesh = {Animals ; Bacteria/*growth & development ; Decapodiformes/*microbiology ; Female ; Ovum/microbiology ; Seawater ; *Symbiosis ; },
abstract = {Female Hawaiian bobtail squid, Euprymna scolopes, have an accessory nidamental gland (ANG) housing a bacterial consortium that is hypothesized to be environmentally transmitted and to function in the protection of eggs from fouling and infection. The composition, stability, and variability of the ANG and egg jelly coat (JC) communities were characterized and compared to the bacterial community composition of the surrounding environment using Illumina sequencing and transmission electron microscopy. The ANG bacterial community was conserved throughout hosts collected from the wild and was not affected by maintaining animals in the laboratory. The core symbiotic community was composed of Alphaproteobacteria and Opitutae (a class of Verrucomicrobia). Operational taxonomic units representing 94.5% of the average ANG abundance were found in either the seawater or sediment, which is consistent with the hypothesis of environmental transmission between generations. The bacterial composition of the JC was stable during development and mirrored that of the ANG. Bacterial communities from individual egg clutches also grouped with the ANG of the female that produced them. Collectively, these data suggest a conserved role of the ANG/JC community in host reproduction. Future directions will focus on determining the function of this symbiotic community, and how it may change during ANG development.},
}
@article {pmid28018314,
year = {2016},
author = {Mandel, MJ and Dunn, AK},
title = {Impact and Influence of the Natural Vibrio-Squid Symbiosis in Understanding Bacterial-Animal Interactions.},
journal = {Frontiers in microbiology},
volume = {7},
number = {},
pages = {1982},
doi = {10.3389/fmicb.2016.01982},
pmid = {28018314},
issn = {1664-302X},
support = {R21 AI117262/AI/NIAID NIH HHS/United States ; R35 GM119627/GM/NIGMS NIH HHS/United States ; },
abstract = {Animals are colonized by bacteria, and in many cases partners have co-evolved to perform mutually beneficial functions. An exciting and ongoing legacy of the past decade has been an expansion of technology to enable study of natural associations in situ/in vivo. As a result, more symbioses are being examined, and additional details are being revealed for well-studied systems with a focus on the interactions between partners in the native context. With this framing, we review recent literature from the Vibrio fischeri-Euprymna scolopes symbiosis and focus on key studies that have had an impact on understanding bacteria-animal interactions broadly. This is not intended to be a comprehensive review of the system, but rather to focus on particular studies that have excelled at moving from pattern to process in facilitating an understanding of the molecular basis to intriguing observations in the field of host-microbe interactions. In this review we discuss the following topics: processes regulating strain and species specificity; bacterial signaling to host morphogenesis; multiple roles for nitric oxide; flagellar motility and chemotaxis; and efforts to understand unannotated and poorly annotated genes. Overall these studies demonstrate how functional approaches in vivo in a tractable system have provided valuable insight into general principles of microbe-host interactions.},
}
@article {pmid28003196,
year = {2017},
author = {Lyell, NL and Septer, AN and Dunn, AK and Duckett, D and Stoudenmire, JL and Stabb, EV},
title = {An Expanded Transposon Mutant Library Reveals that Vibrio fischeri δ-Aminolevulinate Auxotrophs Can Colonize Euprymna scolopes.},
journal = {Applied and environmental microbiology},
volume = {83},
number = {5},
pages = {},
doi = {10.1128/AEM.02470-16},
pmid = {28003196},
issn = {1098-5336},
mesh = {Alanine/metabolism ; Aliivibrio/genetics/growth & development ; Aliivibrio fischeri/*genetics/growth & development/*metabolism/physiology ; Aminolevulinic Acid/metabolism ; Animals ; Bacterial Proteins/genetics ; DNA Transposable Elements/*genetics ; Decapodiformes/*microbiology/physiology ; Gene Library ; Genes, Bacterial/genetics ; Glutamic Acid/metabolism ; Hemin/metabolism ; Host-Pathogen Interactions/physiology ; Light ; Membrane Proteins/genetics ; Mutation ; Peptidoglycan/metabolism ; Phenotype ; Photobacterium/genetics/metabolism ; Symbiosis/*genetics/*physiology ; Virulence ; },
abstract = {Libraries of defined mutants are valuable research tools but necessarily lack gene knockouts that are lethal under the conditions used in library construction. In this study, we augmented a Vibrio fischeri mutant library generated on a rich medium (LBS, which contains [per liter] 10 g of tryptone, 5 g of yeast extract, 20 g of NaCl, and 50 mM Tris [pH 7.5]) by selecting transposon insertion mutants on supplemented LBS and screening for those unable to grow on LBS. We isolated strains with insertions in alr, glr (murI), glmS, several heme biosynthesis genes, and ftsA, as well as a mutant disrupted 14 bp upstream of ftsQ Mutants with insertions in ftsA or upstream of ftsQ were recovered by addition of Mg2+ to LBS, but their cell morphology and motility were affected. The ftsA mutant was more strongly affected and formed cells or chains of cells that appeared to wind back on themselves helically. Growth of mutants with insertions in glmS, alr, or glr was recovered with N-acetylglucosamine (NAG), d-alanine, or d-glutamate, respectively. We hypothesized that NAG, d-alanine, or d-glutamate might be available to V. fischeri in the Euprymna scolopes light organ; however, none of these mutants colonized the host effectively. In contrast, hemA and hemL mutants, which are auxotrophic for δ-aminolevulinate (ALA), colonized at wild-type levels, although mutants later in the heme biosynthetic pathway were severely impaired or unable to colonize. Our findings parallel observations that legume hosts provide Bradyrhizobium symbionts with ALA, but they contrast with virulence phenotypes of hemA mutants in some pathogens. The results further inform our understanding of the symbiotic light organ environment.IMPORTANCE By supplementing a rich yeast-based medium, we were able to recover V. fischeri mutants with insertions in conditionally essential genes, and further characterization of these mutants provided new insights into this bacterium's symbiotic environment. Most notably, we show evidence that the squid host can provide V. fischeri with enough ALA to support its growth in the light organ, paralleling the finding that legumes provide Bradyrhizobium ALA in symbiotic nodules. Taken together, our results show how a simple method of augmenting already rich media can expand the reach and utility of defined mutant libraries.},
}
@article {pmid27062511,
year = {2016},
author = {Heath-Heckman, EA and Foster, J and Apicella, MA and Goldman, WE and McFall-Ngai, M},
title = {Environmental cues and symbiont microbe-associated molecular patterns function in concert to drive the daily remodelling of the crypt-cell brush border of the Euprymna scolopes light organ.},
journal = {Cellular microbiology},
volume = {18},
number = {11},
pages = {1642-1652},
doi = {10.1111/cmi.12602},
pmid = {27062511},
issn = {1462-5822},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM007215/GM/NIGMS NIH HHS/United States ; P30 DK054759/DK/NIDDK NIH HHS/United States ; NNX13AM44G//NASA/United States ; R01 OD011024/OD/NIH HHS/United States ; R01 AI108255/AI/NIAID NIH HHS/United States ; },
mesh = {Animals ; Circadian Rhythm ; Decapodiformes/cytology/microbiology/*physiology ; Epithelial Cells/microbiology/ultrastructure ; Light ; Microvilli/*microbiology/ultrastructure ; Sense Organs/cytology/microbiology ; Symbiosis/radiation effects ; Vibrio/*physiology ; },
abstract = {Recent research has shown that the microbiota affects the biology of associated host epithelial tissues, including their circadian rhythms, although few data are available on how such influences shape the microarchitecture of the brush border. The squid-vibrio system exhibits two modifications of the brush border that supports the symbionts: effacement and repolarization. Together these occur on a daily rhythm in adult animals, at the dawn expulsion of symbionts into the environment, and symbiont colonization of the juvenile host induces an increase in microvillar density. Here we sought to define how these processes are related and the roles of both symbiont colonization and environmental cues. Ultrastructural analyses showed that the juvenile-organ brush borders also efface concomitantly with daily dawn-cued expulsion of symbionts. Manipulation of the environmental light cue and juvenile symbiotic state demonstrated that this behaviour requires the light cue, but not colonization. In contrast, symbionts were required for the observed increase in microvillar density that accompanies post dawn brush-border repolarization; this increase was induced solely by host exposure to phosphorylated lipid A of symbiont cells. These data demonstrate that a partnering of environmental and symbiont cues shapes the brush border and that microbe-associated molecular patterns play a role in the regulation of brush-border microarchitecture.},
}
@article {pmid27747902,
year = {2017},
author = {Kim, HW and Hong, YJ and Jo, JI and Ha, SD and Kim, SH and Lee, HJ and Rhee, MS},
title = {Raw ready-to-eat seafood safety: microbiological quality of the various seafood species available in fishery, hyper and online markets.},
journal = {Letters in applied microbiology},
volume = {64},
number = {1},
pages = {27-34},
doi = {10.1111/lam.12688},
pmid = {27747902},
issn = {1472-765X},
mesh = {Animals ; Bacillus cereus/isolation & purification ; Colony Count, Microbial ; Escherichia coli O157/isolation & purification ; Fish Products/*microbiology ; Fisheries ; Food Contamination/*analysis ; *Food Microbiology ; *Food Safety ; Foodborne Diseases/*microbiology ; Humans ; Listeria monocytogenes/isolation & purification ; Ostreidae/microbiology ; Salmonella/isolation & purification ; Seafood/*microbiology ; Shellfish/*microbiology ; Staphylococcal Infections ; Staphylococcus aureus/isolation & purification ; Vibrio parahaemolyticus/isolation & purification ; Vibrio vulnificus/isolation & purification ; },
abstract = {Microbiological quality of 206 raw ready-to-eat seafood samples was investigated according to species (gizzard shad, halibut, rockfish, tuna, oyster and squid) and distribution channels (fishery, hyper and online market). Enumeration of aerobic plate count and total coliforms (TC) and pathogenic bacteria (Bacillus cereus, Staphylococcus aureus and Vibrio parahaemolyticus) was performed, and level of microbiological quality was classified into four groups: satisfactory, acceptable, unsatisfactory and unacceptable. Qualitative analysis was also performed for Escherichia coli and eight foodborne pathogens (B. cereus, E. coli O157:H7, Listeria monocytogenes, Salmonella spp., S. aureus, Vibrio cholerae, V. parahaemolyticus, and Vibrio vulnificus). Raw ready-to-eat seafood products revealed 0·5% at an unsatisfactory level and 4·9% at an unacceptable level due to ≥4 log CFU g-1 of TC in squid and ≥3 log CFU g-1 of V. parahaemolyticus in gizzard shad respectively. Gizzard shad was shown to be potentially hazardous, as its sashimi is eaten with its skin attached. Bacillus cereus, E. coli, S. aureus, V. parahaemolyticus and V. vulnificus were qualitatively detected. Samples from the fishery market showed higher detection rate especially in V. parahaemolyticus (21·6%) and V. vulnificus (1·7%) which indicates the need to improve microbiological safety of raw ready-to-eat seafood products in fishery market.

Raw ready-to-eat seafood products like sashimi can be easily contaminated with various bacteria from aquatic environments and human reservoirs, which subsequently bring about a risk in food poisoning due to no heating process before consumption. The results of this study provide comprehensive microbiological data on various species of raw ready-to-eat seafood from various distribution channels. It may contribute to establish reasonable standard and effective strategies to ensure a good microbiological quality of raw ready-to-eat seafood for the safety of meals, like sashimi and sushi.},
}
@article {pmid27744412,
year = {2017},
author = {Dillon, MM and Sung, W and Sebra, R and Lynch, M and Cooper, VS},
title = {Genome-Wide Biases in the Rate and Molecular Spectrum of Spontaneous Mutations in Vibrio cholerae and Vibrio fischeri.},
journal = {Molecular biology and evolution},
volume = {34},
number = {1},
pages = {93-109},
doi = {10.1093/molbev/msw224},
pmid = {27744412},
issn = {1537-1719},
support = {R01 GM036827/GM/NIGMS NIH HHS/United States ; R35 GM122566/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*genetics ; Bias ; DNA Mismatch Repair ; DNA Replication ; Genes, Bacterial ; Genome, Bacterial ; High-Throughput Nucleotide Sequencing ; INDEL Mutation ; *Mutation ; Mutation Rate ; Vibrio cholerae/*genetics ; },
abstract = {The vast diversity in nucleotide composition and architecture among bacterial genomes may be partly explained by inherent biases in the rates and spectra of spontaneous mutations. Bacterial genomes with multiple chromosomes are relatively unusual but some are relevant to human health, none more so than the causative agent of cholera, Vibrio cholerae Here, we present the genome-wide mutation spectra in wild-type and mismatch repair (MMR) defective backgrounds of two Vibrio species, the low-%GC squid symbiont V. fischeri and the pathogen V. cholerae, collected under conditions that greatly minimize the efficiency of natural selection. In apparent contrast to their high diversity in nature, both wild-type V. fischeri and V. cholerae have among the lowest rates for base-substitution mutations (bpsms) and insertion-deletion mutations (indels) that have been measured, below 10-3/genome/generation. Vibrio fischeri and V. cholerae have distinct mutation spectra, but both are AT-biased and produce a surprising number of multi-nucleotide indels. Furthermore, the loss of a functional MMR system caused the mutation spectra of these species to converge, implying that the MMR system itself contributes to species-specific mutation patterns. Bpsm and indel rates varied among genome regions, but do not explain the more rapid evolutionary rates of genes on chromosome 2, which likely result from weaker purifying selection. More generally, the very low mutation rates of Vibrio species correlate inversely with their immense population sizes and suggest that selection may not only have maximized replication fidelity but also optimized other polygenic traits relative to the constraints of genetic drift.},
}
@article {pmid27660622,
year = {2016},
author = {Gromek, SM and Suria, AM and Fullmer, MS and Garcia, JL and Gogarten, JP and Nyholm, SV and Balunas, MJ},
title = {Leisingera sp. JC1, a Bacterial Isolate from Hawaiian Bobtail Squid Eggs, Produces Indigoidine and Differentially Inhibits Vibrios.},
journal = {Frontiers in microbiology},
volume = {7},
number = {},
pages = {1342},
doi = {10.3389/fmicb.2016.01342},
pmid = {27660622},
issn = {1664-302X},
abstract = {Female members of many cephalopod species house a bacterial consortium in the accessory nidamental gland (ANG), part of the reproductive system. These bacteria are deposited into eggs that are then laid in the environment where they must develop unprotected from predation, pathogens, and fouling. In this study, we characterized the genome and secondary metabolite production of Leisingera sp. JC1, a member of the roseobacter clade (Rhodobacteraceae) of Alphaproteobacteria isolated from the jelly coat of eggs from the Hawaiian bobtail squid, Euprymna scolopes. Whole genome sequencing and MLSA analysis revealed that Leisingera sp. JC1 falls within a group of roseobacters associated with squid ANGs. Genome and biochemical analyses revealed the potential for and production of a number of secondary metabolites, including siderophores and acyl-homoserine lactones involved with quorum sensing. The complete biosynthetic gene cluster for the pigment indigoidine was detected in the genome and mass spectrometry confirmed the production of this compound. Furthermore, we investigated the production of indigoidine under co-culture conditions with Vibrio fischeri, the light organ symbiont of E. scolopes, and with other vibrios. Finally, both Leisingera sp. JC1 and secondary metabolite extracts of this strain had differential antimicrobial activity against a number of marine vibrios, suggesting that Leisingera sp. JC1 may play a role in host defense against other marine bacteria either in the eggs and/or ANG. These data also suggest that indigoidine may be partially, but not wholly, responsible for the antimicrobial activity of this squid-associated bacterium.},
}
@article {pmid27474717,
year = {2016},
author = {Verma, SC and Miyashiro, T},
title = {Niche-Specific Impact of a Symbiotic Function on the Persistence of Microbial Symbionts within a Natural Host.},
journal = {Applied and environmental microbiology},
volume = {82},
number = {19},
pages = {5990-5996},
doi = {10.1128/AEM.01770-16},
pmid = {27474717},
issn = {1098-5336},
support = {R00 GM097032/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Animals ; Decapodiformes/*microbiology ; *Luminescence ; *Symbiosis ; },
abstract = {UNLABELLED: How the function of microbial symbionts is affected by their population/consortium structure within a host remains poorly understood. The symbiosis established between Euprymna scolopes and Vibrio fischeri is a well-characterized host-microbe association in which the function and structure of V. fischeri populations within the host are known: V. fischeri populations produce bioluminescence from distinct crypt spaces within a dedicated host structure called the light organ. Previous studies have revealed that luminescence is required for V. fischeri populations to persist within the light organ and that deletion of the lux gene locus, which is responsible for luminescence in V. fischeri, leads to a persistence defect. In this study, we investigated the impact of bioluminescence on V. fischeri population structure within the light organ. We report that the persistence defect is specific to crypt I, which is the most developmentally mature crypt space within the nascent light organ. This result provides insight into the structure/function relationship that will be useful for future mechanistic studies of squid-Vibrio symbiosis. In addition, our report highlights the potential impact of the host developmental program on the spatiotemporal dynamics of host-microbe interactions.

IMPORTANCE: Metazoan development and physiology depend on microbes. The relationship between the symbiotic function of microbes and their spatial structure within the host environment remains poorly understood. Here we demonstrate, using a binary symbiosis, that the host requirement for the symbiotic function of the microbial symbiont is restricted to a specific host environment. Our results also suggest a link between microbial function and host development that may be a fundamental aspect of the more complex host-microbe interactions.},
}
@article {pmid27246572,
year = {2016},
author = {Aschtgen, MS and Lynch, JB and Koch, E and Schwartzman, J and McFall-Ngai, M and Ruby, E},
title = {Rotation of Vibrio fischeri Flagella Produces Outer Membrane Vesicles That Induce Host Development.},
journal = {Journal of bacteriology},
volume = {198},
number = {16},
pages = {2156-2165},
doi = {10.1128/JB.00101-16},
pmid = {27246572},
issn = {1098-5530},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM008505/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01 GM099507/GM/NIGMS NIH HHS/United States ; T32 AI055397/AI/NIAID NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; F32 GM119238/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Cell Membrane ; *Extracellular Vesicles ; Flagella/*physiology ; Lipopolysaccharides ; Rotation ; },
abstract = {UNLABELLED: Using the squid-vibrio association, we aimed to characterize the mechanism through which Vibrio fischeri cells signal morphogenesis of the symbiotic light-emitting organ. The symbiont releases two cell envelope molecules, peptidoglycan (PG) and lipopolysaccharide (LPS) that, within 12 h of light organ colonization, act in synergy to trigger normal tissue development. Recent work has shown that outer membrane vesicles (OMVs) produced by V. fischeri are sufficient to induce PG-dependent morphogenesis; however, the mechanism(s) of OMV release by these bacteria has not been described. Like several genera of both beneficial and pathogenic bacteria, V. fischeri cells elaborate polar flagella that are enclosed by an extension of the outer membrane, whose function remains unclear. Here, we present evidence that along with the well-recognized phenomenon of blebbing from the cell's surface, rotation of this sheathed flagellum also results in the release of OMVs. In addition, we demonstrate that most of the development-inducing LPS is associated with these OMVs and that the presence of the outer membrane protein OmpU but not the LPS O antigen on these OMVs is important in triggering normal host development. These results also present insights into a possible new mechanism of LPS release by pathogens with sheathed flagella.

IMPORTANCE: Determining the function(s) of sheathed flagella in bacteria has been challenging, because no known mutation results only in the loss of this outer membrane-derived casing. Nevertheless, the presence of a sheathed flagellum in such host-associated genera as Vibrio, Helicobacter, and Brucella has led to several proposed functions, including physical protection of the flagella and masking of their immunogenic flagellins. Using the squid-vibrio light organ symbiosis, we demonstrate another role, that of V. fischeri cells require rotating flagella to induce apoptotic cell death within surface epithelium, which is a normal step in the organ's development. Further, we present evidence that this rotation releases apoptosis-triggering lipopolysaccharide in the form of outer membrane vesicles. Such release may also occur by pathogens but with different outcomes for the host.},
}
@article {pmid27139830,
year = {2016},
author = {Salah Ud-Din, AI and Roujeinikova, A},
title = {The periplasmic sensing domain of Vibrio fischeri chemoreceptor protein A (VfcA): cloning, purification and crystallographic analysis.},
journal = {Acta crystallographica. Section F, Structural biology communications},
volume = {72},
number = {Pt 5},
pages = {382-385},
doi = {10.1107/S2053230X16005902},
pmid = {27139830},
issn = {2053-230X},
mesh = {Aliivibrio fischeri/*metabolism ; Bacterial Proteins/chemistry/genetics/*metabolism ; Cloning, Molecular ; Crystallography, X-Ray ; Electrophoresis, Polyacrylamide Gel ; Periplasm/*metabolism ; Recombinant Proteins/chemistry/genetics/metabolism ; },
abstract = {Flagella-mediated motility and chemotaxis towards nutrients are important characteristics of Vibrio fischeri that play a crucial role in the development of its symbiotic relationship with its Hawaiian squid host Euprymna scolopes. The V. fischeri chemoreceptor A (VfcA) mediates chemotaxis toward amino acids. The periplasmic sensory domain of VfcA has been crystallized by the hanging-drop vapour-diffusion method using polyethylene glycol 3350 as a precipitating agent. The crystals belonged to space group P1, with unit-cell parameters a = 39.9, b = 57.0, c = 117.0 Å, α = 88.9, β = 80.5, γ = 89.7°. A complete X-ray diffraction data set has been collected to 1.8 Å resolution using cryocooling conditions and synchrotron radiation.},
}
@article {pmid27128997,
year = {2016},
author = {Bongrand, C and Koch, EJ and Moriano-Gutierrez, S and Cordero, OX and McFall-Ngai, M and Polz, MF and Ruby, EG},
title = {A genomic comparison of 13 symbiotic Vibrio fischeri isolates from the perspective of their host source and colonization behavior.},
journal = {The ISME journal},
volume = {10},
number = {12},
pages = {2907-2917},
doi = {10.1038/ismej.2016.69},
pmid = {27128997},
issn = {1751-7370},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01 GM099507/GM/NIGMS NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; P41 RR001614/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/classification/*genetics/isolation & purification/physiology ; Animals ; Decapodiformes/*microbiology/physiology ; Environment ; Genome, Bacterial ; Genomics ; Host Specificity ; *Symbiosis ; },
abstract = {Newly hatched Euprymna scolopes squid obtain their specific light-organ symbionts from an array of Vibrio (Allivibrio) fischeri strains present in their environment. Two genetically distinct populations of this squid species have been identified, one in Kaneohe Bay (KB), and another in Maunaloa Bay (MB), Oahu. We asked whether symbionts isolated from squid in each of these populations outcompete isolates from the other population in mixed-infection experiments. No relationship was found between a strain's host source (KB or MB) and its ability to competitively colonize KB or MB juveniles in a mixed inoculum. Instead, two colonization behaviors were identified among the 11 KB and MB strains tested: a 'dominant' outcome, in which one strain outcompetes the other for colonization, and a 'sharing' outcome, in which two strains co-colonize the squid. A genome-level comparison of these and other V. fischeri strains suggested that the core genomic structure of this species is both syntenous and highly conserved over time and geographical distance. We also identified ~250 Kb of sequence, encoding 194 dispersed orfs, that was specific to those strains that expressed the dominant colonization behavior. Taken together, the results indicate a link between the genome content of V. fischeri strains and their colonization behavior when initiating a light-organ symbiosis.},
}
@article {pmid27016564,
year = {2016},
author = {Sun, Y and LaSota, ED and Cecere, AG and LaPenna, KB and Larios-Valencia, J and Wollenberg, MS and Miyashiro, T},
title = {Intraspecific Competition Impacts Vibrio fischeri Strain Diversity during Initial Colonization of the Squid Light Organ.},
journal = {Applied and environmental microbiology},
volume = {82},
number = {10},
pages = {3082-3091},
doi = {10.1128/AEM.04143-15},
pmid = {27016564},
issn = {1098-5336},
mesh = {Aliivibrio fischeri/*genetics/*growth & development/physiology ; Animal Structures/*microbiology ; Animals ; Decapodiformes/*microbiology/*physiology ; *Genetic Variation ; Genotype ; Phenotype ; *Symbiosis ; Virulence ; },
abstract = {UNLABELLED: Animal development and physiology depend on beneficial interactions with microbial symbionts. In many cases, the microbial symbionts are horizontally transmitted among hosts, thereby making the acquisition of these microbes from the environment an important event within the life history of each host. The light organ symbiosis established between the Hawaiian squid Euprymna scolopes and the bioluminescent bacterium Vibrio fischeri is a model system for examining how hosts acquire horizontally transmitted microbial symbionts. Recent studies have revealed that the light organ of wild-caught E. scolopes squid contains polyclonal populations of V. fischeri bacteria; however, the function and development of such strain diversity in the symbiosis are unknown. Here, we report our phenotypic and phylogenetic characterizations of FQ-A001, which is a V. fischeri strain isolated directly from the light organ of an E. scolopes individual. Relative to the type strain ES114, FQ-A001 exhibits similar growth in rich medium but displays increased bioluminescence and decreased motility in soft agar. FQ-A001 outcompetes ES114 in colonizing the crypt spaces of the light organs. Remarkably, we find that animals cocolonized with FQ-A001 and ES114 harbor singly colonized crypts, in contrast to the cocolonized crypts observed from competition experiments involving single genotypes. The results with our two-strain system suggest that strain diversity within the squid light organ is a consequence of diversity in the single-strain colonization of individual crypt spaces.

IMPORTANCE: The developmental programs and overall physiologies of most animals depend on diverse microbial symbionts that are acquired from the environment. However, the basic principles underlying how microbes colonize their hosts remain poorly understood. Here, we report our findings of bacterial strain competition within the coevolved animal-microbe symbiosis composed of the Hawaiian squid and bioluminescent bacterium Vibrio fischeri Using fluorescent proteins to differentially label two distinct V. fischeri strains, we find that the strains are unable to coexist in the same niche within the host. Our results suggest that strain competition for distinct colonization sites dictates the strain diversity associated with the host. Our study provides a platform for studying how strain diversity develops within a host.},
}
@article {pmid26977108,
year = {2016},
author = {Brooks, JF and Mandel, MJ},
title = {The Histidine Kinase BinK Is a Negative Regulator of Biofilm Formation and Squid Colonization.},
journal = {Journal of bacteriology},
volume = {198},
number = {19},
pages = {2596-2607},
doi = {10.1128/JB.00037-16},
pmid = {26977108},
issn = {1098-5530},
support = {R25 GM079300/GM/NIGMS NIH HHS/United States ; R25 GM086262/GM/NIGMS NIH HHS/United States ; IOS-1456963//National Science Foundation/International ; },
mesh = {Aliivibrio fischeri/*enzymology/metabolism/*physiology ; Animals ; Biofilms/*growth & development ; Decapodiformes/*microbiology ; Gene Expression Regulation, Bacterial ; Gene Expression Regulation, Enzymologic ; Histidine Kinase/genetics/*metabolism ; },
abstract = {UNLABELLED: Bacterial colonization of animal epithelial tissue is a dynamic process that relies on precise molecular communication. Colonization of Euprymna scolopes bobtail squid by Vibrio fischeri bacteria requires bacterial aggregation in host mucus as the symbiont transitions from a planktonic lifestyle in seawater to a biofilm-associated state in the host. We have identified a gene, binK (biofilm inhibitor kinase; VF_A0360), which encodes an orphan hybrid histidine kinase that negatively regulates the V. fischeri symbiotic biofilm (Syp) in vivo and in vitro We identified binK mutants as exhibiting a colonization advantage in a global genetic screen, a phenotype that we confirmed in controlled competition experiments. Bacterial biofilm aggregates in the host are larger in strains lacking BinK, whereas overexpression of BinK suppresses biofilm formation and squid colonization. Signaling through BinK is required for temperature modulation of biofilm formation at 28°C. Furthermore, we present evidence that BinK acts upstream of SypG, the σ(54)-dependent transcriptional regulator of the syp biofilm locus. The BinK effects are dependent on intact signaling in the RscS-Syp biofilm pathway. Therefore, we propose that BinK antagonizes the signal from RscS and serves as an integral component in V. fischeri biofilm regulation.

IMPORTANCE: Bacterial lifestyle transitions underlie the colonization of animal hosts from environmental reservoirs. Formation of matrix-enclosed, surface-associated aggregates (biofilms) is common in beneficial and pathogenic associations, but investigating the genetic basis of biofilm development in live animal hosts remains a significant challenge. Using the bobtail squid light organ as a model, we analyzed putative colonization factors and identified a histidine kinase that negatively regulates biofilm formation at the host interface. This work reveals a novel in vivo biofilm regulator that influences the transition of bacteria from their planktonic state in seawater to tight aggregates of cells in the host. The study enriches our understanding of biofilm regulation and beneficial colonization by an animal's microbiome.},
}
@article {pmid26724686,
year = {2016},
author = {Seedevi, P and Moovendhan, M and Vairamani, S and Shanmugam, A},
title = {Structural characterization and biomedical properties of sulfated polysaccharide from the gladius of Sepioteuthis lessoniana (Lesson, 1831).},
journal = {International journal of biological macromolecules},
volume = {85},
number = {},
pages = {117-125},
doi = {10.1016/j.ijbiomac.2015.12.066},
pmid = {26724686},
issn = {1879-0003},
mesh = {Animals ; Anti-Bacterial Agents/chemistry/pharmacology ; Antineoplastic Agents/chemistry/pharmacology ; Cell Survival/drug effects ; Decapodiformes/*chemistry ; Disk Diffusion Antimicrobial Tests ; HeLa Cells ; Humans ; Molecular Weight ; Monosaccharides/chemistry ; Polysaccharides/*chemistry ; Proton Magnetic Resonance Spectroscopy ; Spectroscopy, Fourier Transform Infrared ; Sulfates/*chemistry ; },
abstract = {Sulfated polysaccharide was extracted from the internal shell (gladius) of Sepioteuthis lessoniana. The sulfated polysaccharide contained 61.3% of carbohydrate, 0.8% of protein, 28.2% of ash and 1.33% of moisture respectively. The elemental composition was analyzed using CHNS/O analyzer. The molecular weight of sulfated polysaccharide determined through PAGE was found to be as 66 kDa. Monosaccharides analysis revealed that sulfated polysaccharide was composed of rhamnose, galactose, xylose and glucose. The structural features of sulfated polysaccharide were analyzed by FT-IR and NMR spectroscopy. Further the sulfated polysaccharide was evaluated for its antibacterial activity against selected human clinical pathogens, namely Staphylococcus aureus, Klebsiella pneumoniae, Salmonella typhi, Vibrio cholerae, Klebsiella oxytoca, Escherichia coli, Salmonella paratyphi, Proteus mirabilis, Vibrio parahaemolyticus and Streptococcus pyogenes using agar well diffusion method. The polysaccharide has showed good antibacterial activity and MIC and MBC have also been evaluated. The anticancer activity was tested against HeLa cell line by MTT assay. The Cytotoxic Concentration (CC50) was observed as 700 μg/ml and the maximum anticancer activity of 62.89% was recorded at 200 μg/ml; whereas, the lowest of 9.87% was observed at 25 μg/ml. In conclusion, the sulfated polysaccharide is an alternate, non-toxic and cheap source of substance that showed good antibacterial and anticancer acitivity.},
}
@article {pmid26644435,
year = {2015},
author = {Kimbrough, JH and Stabb, EV},
title = {Antisocial luxO Mutants Provide a Stationary-Phase Survival Advantage in Vibrio fischeri ES114.},
journal = {Journal of bacteriology},
volume = {198},
number = {4},
pages = {673-687},
doi = {10.1128/JB.00807-15},
pmid = {26644435},
issn = {1098-5530},
mesh = {Acyl-Butyrolactones/metabolism ; Aliivibrio fischeri/genetics/*growth & development/*metabolism ; Bacterial Proteins/*genetics/metabolism ; Gene Expression Regulation, Bacterial ; Homoserine/metabolism ; Microbial Viability ; Mutation ; Repressor Proteins/*genetics/metabolism ; },
abstract = {UNLABELLED: The squid light organ symbiont Vibrio fischeri controls bioluminescence using two acyl-homoserine lactone pheromone-signaling (PS) systems. The first of these systems to be activated during host colonization, AinS/AinR, produces and responds to N-octanoyl homoserine lactone (C(8)-AHL). We screened activity of a P(ainS)-lacZ transcriptional reporter in a transposon mutant library and found three mutants with decreased reporter activity, low C(8)-AHL output, and other traits consistent with low ainS expression. However, the transposon insertions were unrelated to these phenotypes, and genome resequencing revealed that each mutant had a distinct point mutation in luxO. In the wild type, LuxO is phosphorylated by LuxU and then activates transcription of the small RNA (sRNA) Qrr, which represses ainS indirectly by repressing its activator LitR. The luxO mutants identified here encode LuxU-independent, constitutively active LuxO* proteins. The repeated appearance of these luxO mutants suggested that they had some fitness advantage during construction and/or storage of the transposon mutant library, and we found that luxO* mutants survived better and outcompeted the wild type in prolonged stationary-phase cultures. From such cultures we isolated additional luxO* mutants. In all, we isolated LuxO* allelic variants with the mutations P41L, A91D, F94C, P98L, P98Q, V106A, V106G, T107R, V108G, R114P, L205F, H319R, H324R, and T335I. Based on the current model of the V. fischeri PS circuit, litR knockout mutants should resemble luxO* mutants; however, luxO* mutants outcompeted litR mutants in prolonged culture and had much poorer host colonization competitiveness than is reported for litR mutants, illustrating additional complexities in this regulatory circuit.

IMPORTANCE: Our results provide novel insight into the function of LuxO, which is a key component of pheromone signaling (PS) cascades in several members of the Vibrionaceae. Our results also contribute to an increasingly appreciated aspect of bacterial behavior and evolution whereby mutants that do not respond to a signal from like cells have a selective advantage. In this case, although "antisocial" mutants locked in the PS signal-off mode can outcompete parents, their survival advantage does not require wild-type cells to exploit. Finally, this work strikes a note of caution for those conducting or interpreting experiments in V. fischeri, as it illustrates how pleiotropic mutants could easily and inadvertently be enriched in this bacterium during prolonged culturing.},
}
@article {pmid26635751,
year = {2015},
author = {Augimeri, RV and Varley, AJ and Strap, JL},
title = {Establishing a Role for Bacterial Cellulose in Environmental Interactions: Lessons Learned from Diverse Biofilm-Producing Proteobacteria.},
journal = {Frontiers in microbiology},
volume = {6},
number = {},
pages = {1282},
doi = {10.3389/fmicb.2015.01282},
pmid = {26635751},
issn = {1664-302X},
abstract = {Bacterial cellulose (BC) serves as a molecular glue to facilitate intra- and inter-domain interactions in nature. Biosynthesis of BC-containing biofilms occurs in a variety of Proteobacteria that inhabit diverse ecological niches. The enzymatic and regulatory systems responsible for the polymerization, exportation, and regulation of BC are equally as diverse. Though the magnitude and environmental consequences of BC production are species-specific, the common role of BC-containing biofilms is to establish close contact with a preferred host to facilitate efficient host-bacteria interactions. Universally, BC aids in attachment, adherence, and subsequent colonization of a substrate. Bi-directional interactions influence host physiology, bacterial physiology, and regulation of BC biosynthesis, primarily through modulation of intracellular bis-(3'→5')-cyclic diguanylate (c-di-GMP) levels. Depending on the circumstance, BC producers exhibit a pathogenic or symbiotic relationship with plant, animal, or fungal hosts. Rhizobiaceae species colonize plant roots, Pseudomonadaceae inhabit the phyllosphere, Acetobacteriaceae associate with sugar-loving insects and inhabit the carposphere, Enterobacteriaceae use fresh produce as vehicles to infect animal hosts, and Vibrionaceae, particularly Aliivibrio fischeri, colonize the light organ of squid. This review will highlight the diversity of the biosynthesis and regulation of BC in nature by discussing various examples of Proteobacteria that use BC-containing biofilms to facilitate host-bacteria interactions. Through discussion of current data we will establish new directions for the elucidation of BC biosynthesis, its regulation and its ecophysiological roles.},
}
@article {pmid26567312,
year = {2016},
author = {Nikolakakis, K and Monfils, K and Moriano-Gutierrez, S and Brennan, CA and Ruby, EG},
title = {Characterization of the Vibrio fischeri Fatty Acid Chemoreceptors, VfcB and VfcB2.},
journal = {Applied and environmental microbiology},
volume = {82},
number = {2},
pages = {696-704},
doi = {10.1128/AEM.02856-15},
pmid = {26567312},
issn = {1098-5336},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; AI050661/AI/NIAID NIH HHS/United States ; F32 GM112214/GM/NIGMS NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; OD11024/OD/NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; F32GM112214/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/chemistry/classification/genetics/*metabolism ; Animals ; Bacterial Proteins/genetics/*metabolism ; Decapodiformes/microbiology ; Fatty Acids/chemistry/*metabolism ; Membrane Proteins/genetics/*metabolism ; Methyl-Accepting Chemotaxis Proteins ; Phylogeny ; },
abstract = {Bacteria use a wide variety of methyl-accepting chemotaxis proteins (MCPs) to mediate their attraction to or repulsion from different chemical signals in their environment. The bioluminescent marine bacterium Vibrio fischeri is the monospecific symbiont of the Hawaiian bobtail squid, Euprymna scolopes, and encodes a large repertoire of MCPs that are hypothesized to be used during different parts of its complex, multistage lifestyle. Here, we report the initial characterization of two such MCPs from V. fischeri that are responsible for mediating migration toward short- and medium-chain aliphatic (or fatty) acids. These receptors appear to be distributed among only members of the family Vibrionaceae and are likely descended from a receptor that has been lost by the majority of the members of this family. While chemotaxis greatly enhances the efficiency of host colonization by V. fischeri, fatty acids do not appear to be used as a chemical cue during this stage of the symbiosis. This study presents an example of straight-chain fatty acid chemoattraction and contributes to the growing body of characterized MCP-ligand interactions.},
}
@article {pmid26463160,
year = {2015},
author = {Krasity, BC and Troll, JV and Lehnert, EM and Hackett, KT and Dillard, JP and Apicella, MA and Goldman, WE and Weiss, JP and McFall-Ngai, MJ},
title = {Structural and functional features of a developmentally regulated lipopolysaccharide-binding protein.},
journal = {mBio},
volume = {6},
number = {5},
pages = {e01193-15},
doi = {10.1128/mBio.01193-15},
pmid = {26463160},
issn = {2150-7511},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; P30 ES005605/ES/NIEHS NIH HHS/United States ; T32 GM008692/GM/NIGMS NIH HHS/United States ; T32 AI007414/AI/NIAID NIH HHS/United States ; R01 AI059372/AI/NIAID NIH HHS/United States ; OD11024/OD/NIH HHS/United States ; T32 AI055397/AI/NIAID NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; T32 AI55397/AI/NIAID NIH HHS/United States ; R01 AI097157/AI/NIAID NIH HHS/United States ; },
mesh = {Acute-Phase Proteins/*chemistry/genetics/*metabolism ; Aliivibrio fischeri/chemistry/*physiology ; Animals ; Carrier Proteins/*chemistry/genetics/*metabolism ; Decapodiformes/*growth & development/*microbiology/physiology ; Francisella tularensis/chemistry ; Gene Expression Profiling ; Lipopolysaccharides/metabolism ; Membrane Glycoproteins/*chemistry/genetics/*metabolism ; Neisseria meningitidis/chemistry ; Protein Binding ; *Symbiosis ; Transcription, Genetic ; },
abstract = {UNLABELLED: Mammalian lipopolysaccharide (LPS) binding proteins (LBPs) occur mainly in extracellular fluids and promote LPS delivery to specific host cell receptors. The function of LBPs has been studied principally in the context of host defense; the possible role of LBPs in nonpathogenic host-microbe interactions has not been well characterized. Using the Euprymna scolopes-Vibrio fischeri model, we analyzed the structure and function of an LBP family protein, E. scolopes LBP1 (EsLBP1), and provide evidence for its role in triggering a symbiont-induced host developmental program. Previous studies showed that, during initial host colonization, the LPS of V. fischeri synergizes with peptidoglycan (PGN) monomer to induce morphogenesis of epithelial tissues of the host animal. Computationally modeled EsLBP1 shares some but not all structural features of mammalian LBPs that are thought important for LPS binding. Similar to human LBP, recombinant EsLBP1 expressed in insect cells bound V. fischeri LPS and Neisseria meningitidis lipooligosaccharide (LOS) with nanomolar or greater affinity but bound Francisella tularensis LPS only weakly and did not bind PGN monomer. Unlike human LBP, EsLBP1 did not bind N. meningitidis LOS:CD14 complexes. The eslbp1 transcript was upregulated ~22-fold by V. fischeri at 24 h postinoculation. Surprisingly, this upregulation was not induced by exposure to LPS but, rather, to the PGN monomer alone. Hybridization chain reaction-fluorescent in situ hybridization (HCR-FISH) and immunocytochemistry (ICC) localized eslbp1 transcript and protein in crypt epithelia, where V. fischeri induces morphogenesis. The data presented here provide a window into the evolution of LBPs and the scope of their roles in animal symbioses.

IMPORTANCE: Mammalian lipopolysaccharide (LPS)-binding protein (LBP) is implicated in conveying LPS to host cells and potentiating its signaling activity. In certain disease states, such as obesity, the overproduction of this protein has been a reliable biomarker of chronic inflammation. Here, we describe a symbiosis-induced invertebrate LBP whose tertiary structure and LPS-binding characteristics are similar to those of mammalian LBPs; however, the primary structure of this distantly related squid protein (EsLBP1) differs in key residues previously believed to be essential for LPS binding, suggesting that an alternative strategy exists. Surprisingly, symbiotic expression of eslbp1 is induced by peptidoglycan derivatives, not LPS, a pattern converse to that of RegIIIγ, an important mammalian immunity protein that binds peptidoglycan but whose gene expression is induced by LPS. Finally, EsLBP1 occurs along the apical surfaces of all the host's epithelia, suggesting that it was recruited from a general defensive role to one that mediates specific interactions with its symbiont.},
}
@article {pmid26399913,
year = {2016},
author = {Aschtgen, MS and Wetzel, K and Goldman, W and McFall-Ngai, M and Ruby, E},
title = {Vibrio fischeri-derived outer membrane vesicles trigger host development.},
journal = {Cellular microbiology},
volume = {18},
number = {4},
pages = {488-499},
doi = {10.1111/cmi.12525},
pmid = {26399913},
issn = {1462-5822},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM008505/GM/NIGMS NIH HHS/United States ; OD011024/OD/NIH HHS/United States ; R01 GM099507/GM/NIGMS NIH HHS/United States ; AI050661/AI/NIAID NIH HHS/United States ; GM099507/GM/NIGMS NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Animal Structures/growth & development/microbiology ; Animals ; Decapodiformes/*growth & development/*microbiology ; Exosomes/*metabolism ; *Morphogenesis ; *Symbiosis ; },
abstract = {Outer membrane vesicles (OMV) are critical elements in many host-cell/microbe interactions. Previous studies of the symbiotic association between Euprymna scolopes and Vibrio fischeri had shown that within 12 h of colonizing crypts deep within the squid's light organ, the symbionts trigger an irreversible programme of tissue development in the host. Here, we report that OMV produced by V. fischeri are powerful contributors to this process. The first detectable host response to the OMV is an increased trafficking of macrophage-like cells called haemocytes into surface epithelial tissues. We showed that exposing the squid to other Vibrio species fails to induce this trafficking; however, addition of a high concentration of their OMV, which can diffuse into the crypts, does. We also provide evidence that tracheal cytotoxin released by the symbionts, which can induce haemocyte trafficking, is not part of the OMV cargo, suggesting two distinct mechanisms to induce the same morphogenesis event. By manipulating the timing and localization of OMV signal delivery, we showed that haemocyte trafficking is fully induced only when V. fischeri, the sole species able to reach and grow in the crypts, succeeds in establishing a sustained colonization. Further, our data suggest that the host's detection of OMV serves as a symbiotic checkpoint prior to inducing irreversible morphogenesis.},
}
@article {pmid26384815,
year = {2016},
author = {Schwartzman, JA and Ruby, EG},
title = {A conserved chemical dialog of mutualism: lessons from squid and vibrio.},
journal = {Microbes and infection},
volume = {18},
number = {1},
pages = {1-10},
doi = {10.1016/j.micinf.2015.08.016},
pmid = {26384815},
issn = {1769-714X},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM008505/GM/NIGMS NIH HHS/United States ; AI55397/AI/NIAID NIH HHS/United States ; R01 GM099507/GM/NIGMS NIH HHS/United States ; AI050661/AI/NIAID NIH HHS/United States ; GM099507/GM/NIGMS NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; OD11024/OD/NIH HHS/United States ; T32 AI055397/AI/NIAID NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; },
mesh = {Animals ; Decapodiformes/*microbiology/*physiology ; Immunity, Innate ; Stress, Physiological ; *Symbiosis ; Vibrio/*physiology ; },
abstract = {Microorganisms shape, and are shaped by, their environment. In host-microbe associations, this environment is defined by tissue chemistry, which reflects local and organism-wide physiology, as well as inflammatory status. We review how, in the squid-vibrio mutualism, both partners shape tissue chemistry, revealing common themes governing tissue homeostasis in animal-microbe associations.},
}
@article {pmid26286981,
year = {2015},
author = {Carey, J},
title = {News Feature: Intimate partnerships.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {112},
number = {33},
pages = {10071-10073},
doi = {10.1073/pnas.1514276112},
pmid = {26286981},
issn = {1091-6490},
mesh = {Aliivibrio fischeri ; Animals ; Biological Evolution ; Chloroplasts/genetics ; Decapodiformes/microbiology ; Genome ; Genome, Bacterial ; Genome, Mitochondrial ; Insecta/microbiology ; Symbiosis/*physiology ; },
}
@article {pmid26284045,
year = {2015},
author = {Thompson, CM and Visick, KL},
title = {Assessing the function of STAS domain protein SypA in Vibrio fischeri using a comparative analysis.},
journal = {Frontiers in microbiology},
volume = {6},
number = {},
pages = {760},
doi = {10.3389/fmicb.2015.00760},
pmid = {26284045},
issn = {1664-302X},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; },
abstract = {Colonization of the squid Euprymna scolopes by Vibrio fischeri requires biofilm formation dependent on the 18-gene symbiosis polysaccharide locus, syp. One key regulator, SypA, controls biofilm formation by an as-yet unknown mechanism; however, it is known that SypA itself is regulated by SypE. Biofilm-proficient strains form wrinkled colonies on solid media, while sypA mutants form biofilm-defective smooth colonies. To begin to understand the function of SypA, we used comparative analyses and mutagenesis approaches. sypA (and the syp locus) is conserved in other Vibrios, including two food-borne human pathogens, Vibrio vulnificus (rbdA) and Vibrio parahaemolyticus (sypA VP). We found that both homologs could complement the biofilm defect of the V. fischeri sypA mutant, but their phenotypes varied depending on the biofilm-inducing conditions used. Furthermore, while SypAVP retained an ability to be regulated by SypE, RbdA was resistant to this control. To better understand SypA function, we examined the biofilm-promoting ability of a number of mutant SypA proteins with substitutions in conserved residues, and found many that were biofilm-defective. The most severe biofilm-defective phenotypes occurred when changes were made to a conserved stretch of amino acids within a predicted α-helix of SypA; we hypothesize that this region of SypA may interact with another protein to promote biofilm formation. Finally, we identified a residue required for negative control by SypE. Together, our data provide insights into the function of this key biofilm regulator and suggest that the SypA orthologs may play similar roles in their native Vibrio species.},
}
@article {pmid26236308,
year = {2015},
author = {Sun, Y and Verma, SC and Bogale, H and Miyashiro, T},
title = {NagC represses N-acetyl-glucosamine utilization genes in Vibrio fischeri within the light organ of Euprymna scolopes.},
journal = {Frontiers in microbiology},
volume = {6},
number = {},
pages = {741},
doi = {10.3389/fmicb.2015.00741},
pmid = {26236308},
issn = {1664-302X},
support = {R00 GM097032/GM/NIGMS NIH HHS/United States ; },
abstract = {Bacteria often use transcription factors to regulate the expression of metabolic genes in accordance to available nutrients. NagC is a repressor conserved among γ-proteobacteria that regulates expression of enzymes involved in the metabolism of N-acetyl-glucosamine (GlcNAc). The polymeric form of GlcNAc, known as chitin, has been shown to play roles in chemotactic signaling and nutrition within the light organ symbiosis established between the marine bacterium Vibrio fischeri and the Hawaiian squid Euprymna scolopes. Here, we investigate the impact of NagC regulation on the physiology of V. fischeri. We find that NagC repression contributes to the fitness of V. fischeri in the absence of GlcNAc. In addition, the inability to de-repress expression of NagC-regulated genes reduces the fitness of V. fischeri in the presence of GlcNAc. We find that chemotaxis toward GlcNAc or chitobiose, a dimeric form of GlcNAc, is independent of NagC regulation. Finally, we show that NagC represses gene expression during the early stages of symbiosis. Our data suggest that the ability to regulate gene expression with NagC contributes to the overall fitness of V. fischeri in environments that vary in levels of GlcNAc. Furthermore, our finding that NagC represses gene expression within the squid light organ during an early stage of symbiosis supports the notion that the ability of the squid to provide a source of GlcNAc emerges later in host development.},
}
@article {pmid26192462,
year = {2015},
author = {Liu, HH and He, JY and Chi, CF and Lv, ZM},
title = {Identification and analysis of HSP70 from Sepiella maindroni under stress of Vibrio harveyi and Cd(2.).},
journal = {Gene},
volume = {572},
number = {1},
pages = {146-152},
doi = {10.1016/j.gene.2015.07.056},
pmid = {26192462},
issn = {1879-0038},
mesh = {Amino Acid Sequence ; Animals ; Base Sequence ; Cadmium/*toxicity ; Cloning, Molecular ; DNA, Complementary/genetics ; Decapodiformes/drug effects/*genetics/*virology ; Environment ; HSP70 Heat-Shock Proteins/*genetics ; Liver/metabolism/microbiology ; Molecular Sequence Data ; Phylogeny ; RNA, Messenger/genetics/metabolism ; Sequence Homology, Amino Acid ; Stress, Physiological ; Vibrio/*pathogenicity ; },
abstract = {The 70-kDa heat shock proteins (HSP70) play crucial roles in protecting cells against environmental stresses, such as heat shock, heavy metals and pathogenic bacteria. The full-length HSP70 cDNA of Sepiella maindroni (designated as SmHSP70, GenBank accession no. KJ739788) was 2109 bp, including an ORF of 1950 bp encoding a polypeptide of 649 amino acids with predicted pI/MW 5.24/71.30 kDa, a 62 bp-5'-UTR and a 97 bp-3'-UTR. BLASTp analysis and phylogenetic relationship strongly suggested that the amino acid sequence was a member of HSP70 family. Multiple sequence alignment revealed that SmHSP70 and other known HSP70 were highly conserved, especially in the regions of HSP70 family signatures, the bipartite nuclear targeting sequence, ATP/GTP-binding site motif and 'EEVD' motif. Time-dependent mRNA expression of SmHSP70 in the liver was recorded by quantitative real-time RT-PCR after Vibrio harveyi injection and Cd(2+) exposure. The results indicated that SmHSP70 played a significant role in mediating the environmental stress and immune response against pathogens.},
}
@article {pmid26173698,
year = {2015},
author = {Pan, M and Schwartzman, JA and Dunn, AK and Lu, Z and Ruby, EG},
title = {A Single Host-Derived Glycan Impacts Key Regulatory Nodes of Symbiont Metabolism in a Coevolved Mutualism.},
journal = {mBio},
volume = {6},
number = {4},
pages = {e00811},
doi = {10.1128/mBio.00811-15},
pmid = {26173698},
issn = {2150-7511},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM008505/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; AI050661/AI/NIAID NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; OD11024/OD/NIH HHS/United States ; T32 AI055397/AI/NIAID NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; },
mesh = {Acetates/metabolism ; Aliivibrio fischeri/growth & development/metabolism/*physiology ; Animals ; Chitin/*metabolism ; Decapodiformes/*microbiology/*physiology ; Fermentation ; Luminescence ; Oxygen/metabolism ; Phosphoenolpyruvate Sugar Phosphotransferase System/metabolism ; *Symbiosis ; },
abstract = {UNLABELLED: Most animal-microbe mutualistic associations are characterized by nutrient exchange between the partners. When the host provides the nutrients, it can gain the capacity to shape its microbial community, control the stability of the interaction, and promote its health and fitness. Using the bioluminescent squid-vibrio model, we demonstrate how a single host-derived glycan, chitin, regulates the metabolism of Vibrio fischeri at key points in the development and maintenance of the symbiosis. We first characterized the pathways for catabolism of chitin sugars by V. fischeri, demonstrating that the Ccr-dependent phosphoenolpyruvate-pyruvate phosphotransferase system (PTS) prioritizes transport of these sugars in V. fischeri by blocking the uptake of non-PTS carbohydrates, such as glycerol. Next, we found that PTS transport of chitin sugars into the bacterium shifted acetate homeostasis toward a net excretion of acetate and was sufficient to override an activation of the acetate switch by AinS-dependent quorum sensing. Finally, we showed that catabolism of chitin sugars decreases the rate of cell-specific oxygen consumption. Collectively, these three metabolic functions define a physiological shift that favors fermentative growth on chitin sugars and may support optimal symbiont luminescence, the functional basis of the squid-vibrio mutualism.

IMPORTANCE: Host-derived glycans have recently emerged as a link between symbiont nutrition and innate immune function. Unfortunately, the locations at which microbes typically access host-derived glycans are inaccessible to experimentation and imaging, and they take place in the context of diverse microbe-microbe interactions, creating a complex symbiotic ecology. Here we describe the metabolic state of a single microbial symbiont in a natural association with its coevolved host and, by doing so, infer key points at which a host-controlled tissue environment might regulate the physiological state of its symbionts. We show that the presence of a regulatory glycan is sufficient to shift symbiont carbohydrate catabolism, acetate homeostasis, and oxygen consumption.},
}
@article {pmid26168161,
year = {2015},
author = {Cornet, V and Henry, J and Goux, D and Duval, E and Bernay, B and Le Corguillé, G and Corre, E and Zatylny-Gaudin, C},
title = {How Egg Case Proteins Can Protect Cuttlefish Offspring?.},
journal = {PloS one},
volume = {10},
number = {7},
pages = {e0132836},
doi = {10.1371/journal.pone.0132836},
pmid = {26168161},
issn = {1932-6203},
mesh = {Animals ; Decapodiformes/*physiology ; Electrophoresis, Polyacrylamide Gel ; Female ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; *Ovum ; },
abstract = {Sepia officinalis egg protection is ensured by a complex capsule produced by the female accessory genital glands and the ink bag. Our study is focused on the proteins constituting the main egg case. De novo transcriptomes from female genital glands provided essential databases for protein identification. A proteomic approach in SDS-PAGE coupled with MS unveiled a new egg case protein family: SepECPs, for Sepia officinalis Egg Case Proteins. N-glycosylation was demonstrated by PAS staining SDS-PAGE gels. These glycoproteins are mainly produced in the main nidamental glands. SepECPs share high sequence homology, especially in the signal peptide and the three cysteine-rich domains. SepECPs have a high number of cysteines, with conserved motifs involved in 3D-structure. SDS-PAGE showed that SepECPs could form dimers; this result was confirmed by TEM observations, which also revealed a protein network. This network is similar to the capsule network, and it associates these structural proteins with polysaccharides, melanin and bacteria to form a tight mesh. Its hardness and elasticity provide physical protection to the embryo. In addition, SepECPs also have bacteriostatic antimicrobial activity on GRAM- bacteria. By observing the SepECP / Vibrio aestuarianus complex in SEM, we demonstrated the ability of these proteins to agglomerate bacteria and thus inhibit their growth. These original proteins identified from the outer egg case ensure the survival of the species by providing physical and chemical protection to the embryos released in the environment without any maternal protection.},
}
@article {pmid26143243,
year = {2015},
author = {Cornet, V and Henry, J and Corre, E and Le Corguillé, G and Zatylny-Gaudin, C},
title = {The Toll/NF-κB pathway in cuttlefish symbiotic accessory nidamental gland.},
journal = {Developmental and comparative immunology},
volume = {53},
number = {1},
pages = {42-46},
doi = {10.1016/j.dci.2015.06.016},
pmid = {26143243},
issn = {1879-0089},
mesh = {Animals ; Genitalia/*metabolism ; Immunity, Innate/*immunology ; Microbiota/immunology ; NF-kappa B/*genetics/metabolism ; Nitric Oxide Synthase Type II/genetics ; Sepia/*genetics/immunology/metabolism ; Signal Transduction ; Symbiosis ; Toll-Like Receptors/*genetics/metabolism ; Transcriptome/genetics ; },
abstract = {The female genital apparatus of decapod cephalopods contains a symbiotic accessory nidamental gland (ANG) that harbors bacterial symbionts. Although the ANG bacterial consortium is now well described, the impact of symbiosis on Sepia officinalis innate immunity pathways remains unknown. In silico analysis of the de novo transcriptome of ANG highlighted for the first time the existence of the NF-κB pathway in S. officinalis. Several signaling components were identified, i.e. five Toll-like receptors, eight signaling cascade features, and the immune response target gene iNOS, previously described as being involved in the initiation of bacterial symbiosis in a cephalopod gland. This work provides a first key for studying bacterial symbiosis and its impact on innate immunity in S. officinalis ANG.},
}
@article {pmid26062003,
year = {2015},
author = {Colton, DM and Stoudenmire, JL and Stabb, EV},
title = {Growth on glucose decreases cAMP-CRP activity while paradoxically increasing intracellular cAMP in the light-organ symbiont Vibrio fischeri.},
journal = {Molecular microbiology},
volume = {97},
number = {6},
pages = {1114-1127},
doi = {10.1111/mmi.13087},
pmid = {26062003},
issn = {1365-2958},
mesh = {ATP-Binding Cassette Transporters/*metabolism ; Aliivibrio fischeri/chemistry/*growth & development/*metabolism ; Bacterial Proteins/*genetics/metabolism ; Carrier Proteins/metabolism ; Cyclic AMP/*metabolism ; Glucose/metabolism ; Helicobacter pylori/genetics/metabolism ; Metals/metabolism ; Nitric Oxide/metabolism ; *Transcription, Genetic ; },
abstract = {Proteobacteria often co-ordinate responses to carbon sources using CRP and the second messenger cyclic 3', 5'-AMP (cAMP), which combine to control transcription of genes during growth on non-glucose substrates as part of the catabolite-repression response. Here we show that cAMP-CRP is active and important in Vibrio fischeri during colonization of its host squid Euprymna scolopes. Moreover, consistent with a classical role in catabolite repression, a cAMP-CRP-dependent reporter showed lower activity in cells grown in media amended with glucose rather than glycerol. Surprisingly though, intracellular cAMP levels were higher in glucose-grown cells. Mutant analyses were consistent with predictions that CyaA was responsible for cAMP generation, that the EIIA(Glc) component of glucose transport could enhance cAMP production and that the phophodiesterases CpdA and CpdP consumed intracellular and extracellular cAMP respectively. However, the observation of lower cAMP levels in glycerol-grown cells seemed best explained by changes in cAMP export, via an unknown mechanism. Our data also indicated that cAMP-CRP activity decreased during growth on glucose independently of crp's native transcriptional regulation or cAMP levels. We speculate that some unknown mechanism, perhaps carbon-source-dependent post-translational modulation of CRP, may help control cAMP-CRP activity in V.fischeri.},
}
@article {pmid26025891,
year = {2015},
author = {Singh, P and Brooks, JF and Ray, VA and Mandel, MJ and Visick, KL},
title = {CysK Plays a Role in Biofilm Formation and Colonization by Vibrio fischeri.},
journal = {Applied and environmental microbiology},
volume = {81},
number = {15},
pages = {5223-5234},
doi = {10.1128/AEM.00157-15},
pmid = {26025891},
issn = {1098-5336},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; GM08061/GM/NIGMS NIH HHS/United States ; R25 GM079300/GM/NIGMS NIH HHS/United States ; T32 GM008061/GM/NIGMS NIH HHS/United States ; R25 GM086262/GM/NIGMS NIH HHS/United States ; R01 GM59690/GM/NIGMS NIH HHS/United States ; OD11024/OD/NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/growth & development/metabolism/*physiology ; Animals ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Biosynthetic Pathways/genetics ; Culture Media/chemistry ; Cysteine/metabolism ; Cysteine Synthase/genetics/*metabolism ; Decapodiformes/microbiology ; Genetic Complementation Test ; Genetic Testing ; Mutation ; },
abstract = {A biofilm, or a matrix-embedded community of cells, promotes the ability of the bacterium Vibrio fischeri to colonize its symbiotic host, the Hawaiian squid Euprymna scolopes. Biofilm formation and colonization depend on syp, an 18-gene polysaccharide locus. To identify other genes necessary for biofilm formation, we screened for mutants that failed to form wrinkled colonies, a type of biofilm. We obtained several with defects in genes required for cysteine metabolism, including cysH, cysJ, cysK, and cysN. The cysK mutant exhibited the most severe wrinkling defect. It could be complemented with a wild-type copy of the cysK gene, which encodes O-acetylserine sulfhydrolase, or by supplementing the medium with additional cysteine. None of a number of other mutants defective for biosynthetic genes negatively impacted wrinkled colony formation, suggesting a specific role for CysK. CysK did not appear to control activation of Syp regulators or transcription of the syp locus, but it did influence production of the Syp polysaccharide. Under biofilm-inducing conditions, the cysK mutant retained the same ability as that of the parent strain to adhere to the agar surface. The cysK mutant also exhibited a defect in pellicle production that could be complemented by the cysK gene but not by cysteine, suggesting that, under these conditions, CysK is important for more than the production of cysteine. Finally, our data reveal a role for cysK in symbiotic colonization by V. fischeri. Although many questions remain, this work provides insights into additional factors required for biofilm formation and colonization by V. fischeri.},
}
@article {pmid25956763,
year = {2015},
author = {Nikolakakis, K and Lehnert, E and McFall-Ngai, MJ and Ruby, EG},
title = {Use of Hybridization Chain Reaction-Fluorescent In Situ Hybridization To Track Gene Expression by Both Partners during Initiation of Symbiosis.},
journal = {Applied and environmental microbiology},
volume = {81},
number = {14},
pages = {4728-4735},
doi = {10.1128/AEM.00890-15},
pmid = {25956763},
issn = {1098-5336},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; AI050661/AI/NIAID NIH HHS/United States ; F32 GM112214/GM/NIGMS NIH HHS/United States ; OD11024/OD/NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; F32GM112214/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*genetics/growth & development/physiology ; Animals ; Bacterial Proteins/genetics/metabolism ; Decapodiformes/*genetics/*microbiology/physiology ; In Situ Hybridization, Fluorescence/*methods ; *Symbiosis ; },
abstract = {The establishment of a productive symbiosis between Euprymna scolopes, the Hawaiian bobtail squid, and its luminous bacterial symbiont, Vibrio fischeri, is mediated by transcriptional changes in both partners. A key challenge to unraveling the steps required to successfully initiate this and many other symbiotic associations is characterization of the timing and location of these changes. We report on the adaptation of hybridization chain reaction-fluorescent in situ hybridization (HCR-FISH) to simultaneously probe the spatiotemporal regulation of targeted genes in both E. scolopes and V. fischeri. This method revealed localized, transcriptionally coregulated epithelial cells within the light organ that responded directly to the presence of bacterial cells while, at the same time, provided a sensitive means to directly show regulated gene expression within the symbiont population. Thus, HCR-FISH provides a new approach for characterizing habitat transition in bacteria and for discovering host tissue responses to colonization.},
}
@article {pmid25775132,
year = {2015},
author = {Salazar, KA and Joffe, NR and Dinguirard, N and Houde, P and Castillo, MG},
title = {Transcriptome analysis of the white body of the squid Euprymna tasmanica with emphasis on immune and hematopoietic gene discovery.},
journal = {PloS one},
volume = {10},
number = {3},
pages = {e0119949},
doi = {10.1371/journal.pone.0119949},
pmid = {25775132},
issn = {1932-6203},
mesh = {Aliivibrio fischeri/*immunology ; Animals ; *Decapodiformes/genetics/immunology/metabolism/microbiology ; Gene Expression Regulation/*immunology ; *Hematopoiesis/genetics/immunology ; Immunity/*genetics ; Transcriptome/*immunology ; },
abstract = {In the mutualistic relationship between the squid Euprymna tasmanica and the bioluminescent bacterium Vibrio fischeri, several host factors, including immune-related proteins, are known to interact and respond specifically and exclusively to the presence of the symbiont. In squid and octopus, the white body is considered to be an immune organ mainly due to the fact that blood cells, or hemocytes, are known to be present in high numbers and in different developmental stages. Hence, the white body has been described as the site of hematopoiesis in cephalopods. However, to our knowledge, there are no studies showing any molecular evidence of such functions. In this study, we performed a transcriptomic analysis of white body tissue of the Southern dumpling squid, E. tasmanica. Our primary goal was to gain insights into the functions of this tissue and to test for the presence of gene transcripts associated with hematopoietic and immune processes. Several hematopoiesis genes including CPSF1, GATA 2, TFIID, and FGFR2 were found to be expressed in the white body. In addition, transcripts associated with immune-related signal transduction pathways, such as the toll-like receptor/NF-κβ, and MAPK pathways were also found, as well as other immune genes previously identified in E. tasmanica's sister species, E. scolopes. This study is the first to analyze an immune organ within cephalopods, and to provide gene expression data supporting the white body as a hematopoietic tissue.},
}
@article {pmid25755651,
year = {2015},
author = {Collins, AJ and Fullmer, MS and Gogarten, JP and Nyholm, SV},
title = {Comparative genomics of Roseobacter clade bacteria isolated from the accessory nidamental gland of Euprymna scolopes.},
journal = {Frontiers in microbiology},
volume = {6},
number = {},
pages = {123},
doi = {10.3389/fmicb.2015.00123},
pmid = {25755651},
issn = {1664-302X},
abstract = {The accessory nidamental gland (ANG) of the female Hawaiian bobtail squid, Euprymna scolopes, houses a consortium of bacteria including members of the Flavobacteriales, Rhizobiales, and Verrucomicrobia but is dominated by members of the Roseobacter clade (Rhodobacterales) within the Alphaproteobacteria. These bacteria are deposited into the jelly coat of the squid's eggs, however, the function of the ANG and its bacterial symbionts has yet to be elucidated. In order to gain insight into this consortium and its potential role in host reproduction, we cultured 12 Rhodobacterales isolates from ANGs of sexually mature female squid and sequenced their genomes with Illumina sequencing technology. For taxonomic analyses, the ribosomal proteins of 79 genomes representing both roseobacters and non-roseobacters along with a separate MLSA analysis of 33 housekeeping genes from Roseobacter organisms placed all 12 isolates from the ANG within two groups of a single Roseobacter clade. Average nucelotide identity analysis suggests the ANG isolates represent three genera (Leisingera, Ruegeria, and Tateyamaria) comprised of seven putative species groups. All but one of the isolates contains a predicted Type VI secretion system, which has been shown to be important in secreting signaling and/or effector molecules in host-microbe associations and in bacteria-bacteria interactions. All sequenced genomes also show potential for secondary metabolite production, and are predicted to be involved with the production of acyl homoserine lactones (AHLs) and/or siderophores. An AHL bioassay confirmed AHL production in three tested isolates and from whole ANG homogenates. The dominant symbiont, Leisingera sp. ANG1, showed greater viability in iron-limiting conditions compared to other roseobacters, possibly due to higher levels of siderophore production. Future comparisons will try to elucidate novel metabolic pathways of the ANG symbionts to understand their putative role in host development.},
}
@article {pmid25742727,
year = {2015},
author = {Yazzie, N and Salazar, KA and Castillo, MG},
title = {Identification, molecular characterization, and gene expression analysis of a CD109 molecule in the Hawaiian bobtail squid Euprymna scolopes.},
journal = {Fish & shellfish immunology},
volume = {44},
number = {1},
pages = {342-355},
doi = {10.1016/j.fsi.2015.02.036},
pmid = {25742727},
issn = {1095-9947},
mesh = {Amino Acid Sequence ; Animals ; Antigens, CD/chemistry/*genetics ; Base Sequence ; Decapodiformes/*genetics ; Gene Expression ; Molecular Sequence Data ; Phylogeny ; },
abstract = {All organisms have unique immune systems that help them identify and eliminate invading microorganisms. A group of evolutionary ancient molecules, the thioester-containing proteins (TEP) superfamily, are known to play an important immune role by aiding animal hosts in the recognition, destruction, and elimination of hazardous microorganisms and their products. Our laboratory focuses on studying the role of the immune system in the mutualistic relationship between the sepiolid squid, Euprymna scolopes and its bioluminescent symbiont Vibrio fischeri. In the present study, we report the identification of a novel TEP-like transcript expressed in the light organ of squid. Characterization of the full-length coding sequence showed a molecule of 4218 nucleotides, corresponding to 1406 amino acids. Further sequence analysis revealed it contained structural characteristics of A2M molecules, including the thioester and receptor-binding domains. Analysis using the predicted amino acid sequence suggested this transcript was a homologue of CD109 molecules, thus we named it E. scolopes-CD109 (Es-CD109). In addition to the light organ, we were able to detect and amplify Es-CD109 in 12 out of 14 adult squid tissues tested. Quantification experiments showed that Es-CD109 expression levels were significantly lower in the light organ of symbiotic compared to aposymbiotic juveniles, suggesting a possible down-regulation of the host immune response in the presence of the bacterial symbiont.},
}
@article {pmid25725799,
year = {2015},
author = {Minamoto, T and Takahashi, N and Kitahara, S and Shinozaki, Y and Hirano, T and Hakamata, W and Nishio, T},
title = {Saccharification of β-chitin from squid pen by a fermentation method using recombinant chitinase-secreting Escherichia coli.},
journal = {Applied biochemistry and biotechnology},
volume = {175},
number = {8},
pages = {3788-3799},
doi = {10.1007/s12010-015-1547-9},
pmid = {25725799},
issn = {1559-0291},
mesh = {Animals ; Chitin/*chemistry/metabolism ; Chitinases/*chemistry/genetics/metabolism ; Decapodiformes/chemistry/metabolism ; Escherichia coli/*enzymology/genetics ; Fermentation ; Recombinant Proteins/*chemistry/genetics/metabolism ; Substrate Specificity ; },
abstract = {Two strains [BL21(DE3) and HMS174(DE3)] of Escherichia coli harboring the recombinant chitinase expression plasmid pVP-Chi, which contains Vibrio parahaemolyticus chitinase gene with an attached signal sequence, were prepared. These E. coli transformants produced a large amount of recombinant chitinase, which hydrolyzes chitin to yield di-N-acetylchitobiose (GlcNAc)2, under the presence of isopropyl-1-thio-β-D-galactopyranoside (IPTG), and secreted the enzyme into their culture fluid with the aid of the signal peptide. Cultivation of these E. coli transformants in Luria-Bertani medium containing squid pen β-chitin and IPTG gave rise to the decomposition of this polysaccharide and the accumulation of (GlcNAc)2 in the culture fluid. Through these experiments, we confirmed that the use of strain HMS174(DE3) was preferable for the stable accumulation of (GlcNAc)2 in the culture fluid during cultivation owing to lower (GlcNAc)2 assimilation compared to BL21(DE3). Next, using E. coli HMS174(DE3) transformants, we conducted saccharification of different forms (fluffy fiber, flake, and powder) of β-chitin samples prepared from squid pens in Bacterion-N-KS(B)K medium containing 2 % of each sample under the presence of IPTG. In these experiments, (GlcNAc)2 was isolated with a more than 20 % stoichiometric yield from each culture supernatant through charcoal column chromatography followed by recrystallization.},
}
@article {pmid25592518,
year = {2015},
author = {Yong, E},
title = {Microbiology: Here's looking at you, squid.},
journal = {Nature},
volume = {517},
number = {7534},
pages = {262-264},
doi = {10.1038/517262a},
pmid = {25592518},
issn = {1476-4687},
mesh = {Animals ; Cryptochromes/genetics ; Decapodiformes/genetics/immunology/*microbiology ; Female ; Host Specificity/genetics ; Humans ; Luminescence ; Microbiota/*physiology ; *Symbiosis ; Vibrio/*physiology ; },
}
@article {pmid25586643,
year = {2015},
author = {Norsworthy, AN and Visick, KL},
title = {Signaling between two interacting sensor kinases promotes biofilms and colonization by a bacterial symbiont.},
journal = {Molecular microbiology},
volume = {96},
number = {2},
pages = {233-248},
doi = {10.1111/mmi.12932},
pmid = {25586643},
issn = {1365-2958},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio Infections/microbiology/*veterinary ; Aliivibrio fischeri/*enzymology/genetics/*growth & development/physiology ; Animals ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Decapodiformes/*microbiology ; Gene Expression Regulation, Bacterial ; Protein Kinases/genetics/*metabolism ; Signal Transduction ; Symbiosis ; },
abstract = {Cells acclimate to fluctuating environments by utilizing sensory circuits. One common sensory pathway used by bacteria is two-component signaling (TCS), composed of an environmental sensor [the sensor kinase (SK)] and a cognate, intracellular effector [the response regulator (RR)]. The squid symbiont Vibrio fischeri uses an elaborate TCS phosphorelay containing a hybrid SK, RscS, and two RRs, SypE and SypG, to control biofilm formation and host colonization. Here, we found that another hybrid SK, SypF, was essential for biofilms by functioning downstream of RscS to directly control SypE and SypG. Surprisingly, although wild-type SypF functioned as an SK in vitro, this activity was dispensable for colonization. In fact, only a single non-enzymatic domain within SypF, the HPt domain, was critical in vivo. Remarkably, this domain within SypF interacted with RscS to permit a bypass of RscS's own HPt domain and SypF's enzymatic function. This represents the first in vivo example of a functional SK that exploits the enzymatic activity of another SK, an adaptation that demonstrates the elegant plasticity in the arrangement of TCS regulators.},
}
@article {pmid25578956,
year = {2015},
author = {Kåhrström, CT},
title = {Symbiosis: Sweet talking your partner.},
journal = {Nature reviews. Microbiology},
volume = {13},
number = {2},
pages = {66-67},
doi = {10.1038/nrmicro3424},
pmid = {25578956},
issn = {1740-1534},
mesh = {Aliivibrio fischeri/*metabolism ; Animals ; Decapodiformes/*metabolism/*microbiology ; Polysaccharides/*metabolism ; Symbiosis/*physiology ; },
}
@article {pmid25561715,
year = {2015},
author = {Brooks, JF and Gyllborg, MC and Kocher, AA and Markey, LE and Mandel, MJ},
title = {TfoX-based genetic mapping identifies Vibrio fischeri strain-level differences and reveals a common lineage of laboratory strains.},
journal = {Journal of bacteriology},
volume = {197},
number = {6},
pages = {1065-1074},
doi = {10.1128/JB.02347-14},
pmid = {25561715},
issn = {1098-5530},
support = {R25 GM079300/GM/NIGMS NIH HHS/United States ; R25 GM086262/GM/NIGMS NIH HHS/United States ; T32 GM008061/GM/NIGMS NIH HHS/United States ; GM08061/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/classification/genetics/*metabolism ; Animals ; Bacterial Proteins/genetics/*metabolism ; Carrier State ; *Chromosome Mapping ; Chromosomes, Bacterial/genetics ; DNA, Bacterial ; Decapodiformes/microbiology ; Gene Expression Regulation, Bacterial/*physiology ; Genetic Markers ; Trans-Activators/genetics/*metabolism ; },
abstract = {Bacterial strain variation exists in natural populations of bacteria and can be generated experimentally through directed or random mutation. The advent of rapid and cost-efficient whole-genome sequencing has facilitated strain-level genotyping. Even with modern tools, however, it often remains a challenge to map specific traits to individual genetic loci, especially for traits that cannot be selected under culture conditions (e.g., colonization level or pathogenicity). Using a combination of classical and modern approaches, we analyzed strain-level variation in Vibrio fischeri and identified the basis by which some strains lack the ability to utilize glycerol as a carbon source. We proceeded to reconstruct the lineage of the commonly used V. fischeri laboratory strains. Compared to the wild-type ES114 strain, we identify in ES114-L a 9.9-kb deletion with endpoints in tadB2 and glpF; restoration of the missing portion of glpF restores the wild-type phenotype. The widely used strains ESR1, JRM100, and JRM200 contain the same deletion, and ES114-L is likely a previously unrecognized intermediate strain in the construction of many ES114 derivatives. ES114-L does not exhibit a defect in competitive squid colonization but ESR1 does, demonstrating that glycerol utilization is not required for early squid colonization. Our genetic mapping approach capitalizes on the recently discovered chitin-based transformation pathway, which is conserved in the Vibrionaceae; therefore, the specific approach used is likely to be useful for mapping genetic traits in other Vibrio species.},
}
@article {pmid25550509,
year = {2015},
author = {Schwartzman, JA and Koch, E and Heath-Heckman, EA and Zhou, L and Kremer, N and McFall-Ngai, MJ and Ruby, EG},
title = {The chemistry of negotiation: rhythmic, glycan-driven acidification in a symbiotic conversation.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {112},
number = {2},
pages = {566-571},
doi = {10.1073/pnas.1418580112},
pmid = {25550509},
issn = {1091-6490},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM008505/GM/NIGMS NIH HHS/United States ; T32 GM007215/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01 GM099507/GM/NIGMS NIH HHS/United States ; AI050661/AI/NIAID NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; OD11024/OD/NIH HHS/United States ; T32 AI055397/AI/NIAID NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*metabolism ; Amino Acid Sequence ; Animals ; Base Sequence ; Chitin/genetics/metabolism ; DNA/genetics ; Darkness ; Decapodiformes/genetics/*metabolism/*microbiology ; Genes, Bacterial ; Hemocytes/metabolism ; Hexosaminidases/genetics/metabolism ; Hydrogen-Ion Concentration ; Luminescence ; Molecular Sequence Data ; Mutation ; Oligosaccharides/genetics/metabolism ; Polysaccharides/*metabolism ; Symbiosis/genetics/*physiology ; },
abstract = {Glycans have emerged as critical determinants of immune maturation, microbial nutrition, and host health in diverse symbioses. In this study, we asked how cyclic delivery of a single host-derived glycan contributes to the dynamic stability of the mutualism between the squid Euprymna scolopes and its specific, bioluminescent symbiont, Vibrio fischeri. V. fischeri colonizes the crypts of a host organ that is used for behavioral light production. E. scolopes synthesizes the polymeric glycan chitin in macrophage-like immune cells called hemocytes. We show here that, just before dusk, hemocytes migrate from the vasculature into the symbiotic crypts, where they lyse and release particulate chitin, a behavior that is established only in the mature symbiosis. Diel transcriptional rhythms in both partners further indicate that the chitin is provided and metabolized only at night. A V. fischeri mutant defective in chitin catabolism was able to maintain a normal symbiont population level, but only until the symbiotic organ reached maturity (∼ 4 wk after colonization); this result provided a direct link between chitin utilization and symbiont persistence. Finally, catabolism of chitin by the symbionts was also specifically required for a periodic acidification of the adult crypts each night. This acidification, which increases the level of oxygen available to the symbionts, enhances their capacity to produce bioluminescence at night. We propose that other animal hosts may similarly regulate the activities of epithelium-associated microbial communities through the strategic provision of specific nutrients, whose catabolism modulates conditions like pH or anoxia in their symbionts' habitat.},
}
@article {pmid25538686,
year = {2014},
author = {Soto, W and Nishiguchi, MK},
title = {Microbial experimental evolution as a novel research approach in the Vibrionaceae and squid-Vibrio symbiosis.},
journal = {Frontiers in microbiology},
volume = {5},
number = {},
pages = {593},
doi = {10.3389/fmicb.2014.00593},
pmid = {25538686},
issn = {1664-302X},
support = {SC1 AI081659/AI/NIAID NIH HHS/United States ; },
abstract = {The Vibrionaceae are a genetically and metabolically diverse family living in aquatic habitats with a great propensity toward developing interactions with eukaryotic microbial and multicellular hosts (as either commensals, pathogens, and mutualists). The Vibrionaceae frequently possess a life history cycle where bacteria are attached to a host in one phase and then another where they are free from their host as either part of the bacterioplankton or adhered to solid substrates such as marine sediment, riverbeds, lakebeds, or floating particulate debris. These two stages in their life history exert quite distinct and separate selection pressures. When bound to solid substrates or to host cells, the Vibrionaceae can also exist as complex biofilms. The association between bioluminescent Vibrio spp. and sepiolid squids (Cephalopoda: Sepiolidae) is an experimentally tractable model to study bacteria and animal host interactions, since the symbionts and squid hosts can be maintained in the laboratory independently of one another. The bacteria can be grown in pure culture and the squid hosts raised gnotobiotically with sterile light organs. The partnership between free-living Vibrio symbionts and axenic squid hatchlings emerging from eggs must be renewed every generation of the cephalopod host. Thus, symbiotic bacteria and animal host can each be studied alone and together in union. Despite virtues provided by the Vibrionaceae and sepiolid squid-Vibrio symbiosis, these assets to evolutionary biology have yet to be fully utilized for microbial experimental evolution. Experimental evolution studies already completed are reviewed, along with exploratory topics for future study.},
}
@article {pmid25404340,
year = {2014},
author = {Brooks, JF and Gyllborg, MC and Cronin, DC and Quillin, SJ and Mallama, CA and Foxall, R and Whistler, C and Goodman, AL and Mandel, MJ},
title = {Global discovery of colonization determinants in the squid symbiont Vibrio fischeri.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {111},
number = {48},
pages = {17284-17289},
doi = {10.1073/pnas.1415957111},
pmid = {25404340},
issn = {1091-6490},
support = {GM08061/GM/NIGMS NIH HHS/United States ; R25 GM079300/GM/NIGMS NIH HHS/United States ; T32 GM008061/GM/NIGMS NIH HHS/United States ; R25 GM086262/GM/NIGMS NIH HHS/United States ; K01 DK089121/DK/NIDDK NIH HHS/United States ; DK089121/DK/NIDDK NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*genetics/*physiology ; Animals ; Bacterial Proteins/genetics ; Biofilms ; DNA Transposable Elements/genetics ; Decapodiformes/*microbiology ; Gene Expression Regulation, Bacterial ; Genes, Bacterial/genetics ; High-Throughput Nucleotide Sequencing ; Host-Pathogen Interactions ; Microbiota/*genetics ; Mutagenesis, Insertional ; Reverse Transcriptase Polymerase Chain Reaction ; Symbiosis ; },
abstract = {Animal epithelial tissue becomes reproducibly colonized by specific environmental bacteria. The bacteria (microbiota) perform critical functions for the host's tissue development, immune system development, and nutrition; yet the processes by which bacterial diversity in the environment is selected to assemble the correct communities in the host are unclear. To understand the molecular determinants of microbiota selection, we examined colonization of a simplified model in which the light organ of Euprymna scolopes squid is colonized exclusively by Vibrio fischeri bacteria. We applied high-throughput insertion sequencing to identify which bacterial genes are required during host colonization. A library of over 41,000 unique transposon insertions was analyzed before and after colonization of 1,500 squid hatchlings. Mutants that were reproducibly depleted following squid colonization represented 380 genes, including 37 that encode known colonization factors. Validation of select mutants in defined competitions against the wild-type strain identified nine mutants that exhibited a reproducible colonization defect. Some of the colonization factors identified included genes predicted to influence copper regulation and secretion. Other mutants exhibited defects in biofilm development, which is required for aggregation in host mucus and initiation of colonization. Biofilm formation in culture and in vivo was abolished in a strain lacking the cytoplasmic chaperone DnaJ, suggesting an important role for protein quality control during the elaboration of bacterial biofilm in the context of an intact host immune system. Overall these data suggest that cellular stress responses and biofilm regulation are critical processes underlying the reproducible colonization of animal hosts by specific microbial symbionts.},
}
@article {pmid25336755,
year = {2014},
author = {Pankey, MS and Minin, VN and Imholte, GC and Suchard, MA and Oakley, TH},
title = {Predictable transcriptome evolution in the convergent and complex bioluminescent organs of squid.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {111},
number = {44},
pages = {E4736-42},
doi = {10.1073/pnas.1416574111},
pmid = {25336755},
issn = {1091-6490},
support = {R01 AI107034/AI/NIAID NIH HHS/United States ; R01-AI107034/AI/NIAID NIH HHS/United States ; },
mesh = {Animals ; Bacteria/genetics/*metabolism ; Decapodiformes/genetics/*metabolism ; *Evolution, Molecular ; Gene Expression Regulation/*physiology ; Symbiosis/*physiology ; Transcriptome/*physiology ; },
abstract = {Despite contingency in life's history, the similarity of evolutionarily convergent traits may represent predictable solutions to common conditions. However, the extent to which overall gene expression levels (transcriptomes) underlying convergent traits are themselves convergent remains largely unexplored. Here, we show strong statistical support for convergent evolutionary origins and massively parallel evolution of the entire transcriptomes in symbiotic bioluminescent organs (bacterial photophores) from two divergent squid species. The gene expression similarities are so strong that regression models of one species' photophore can predict organ identity of a distantly related photophore from gene expression levels alone. Our results point to widespread parallel changes in gene expression evolution associated with convergent origins of complex organs. Therefore, predictable solutions may drive not only the evolution of novel, complex organs but also the evolution of overall gene expression levels that underlie them.},
}
@article {pmid25038065,
year = {2014},
author = {Schleicher, TR and VerBerkmoes, NC and Shah, M and Nyholm, SV},
title = {Colonization state influences the hemocyte proteome in a beneficial squid-Vibrio symbiosis.},
journal = {Molecular & cellular proteomics : MCP},
volume = {13},
number = {10},
pages = {2673-2686},
doi = {10.1074/mcp.M113.037259},
pmid = {25038065},
issn = {1535-9484},
mesh = {Aliivibrio fischeri/drug effects/physiology ; Animals ; Anti-Bacterial Agents/pharmacology ; Decapodiformes/*microbiology/*physiology ; Gene Expression Regulation ; Hemocytes/*metabolism ; Proteome/*analysis ; Proteomics/*methods ; Symbiosis ; },
abstract = {The squid Euprymna scolopes and the luminescent bacterium Vibrio fischeri form a highly specific beneficial light organ symbiosis. Not only does the host have to select V. fischeri from the environment, but it must also prevent subsequent colonization by non-symbiotic microorganisms. Host macrophage-like hemocytes are believed to play a role in mediating the symbiosis with V. fischeri. Previous studies have shown that the colonization state of the light organ influences the host's hemocyte response to the symbiont. To further understand the molecular mechanisms behind this process, we used two quantitative mass-spectrometry-based proteomic techniques, isobaric tags for relative and absolute quantification (iTRAQ) and label-free spectral counting, to compare and quantify the adult hemocyte proteomes from colonized (sym) and uncolonized (antibiotic-treated/cured) squid. Overall, iTRAQ allowed for the quantification of 1,024 proteins with two or more peptides. Thirty-seven unique proteins were determined to be significantly different between sym and cured hemocytes (p value < 0.05), with 20 more abundant proteins and 17 less abundant in sym hemocytes. The label-free approach resulted in 1,241 proteins that were identified in all replicates. Of 185 unique proteins present at significantly different amounts in sym hemocytes (as determined by spectral counting), 92 were more abundant and 93 were less abundant. Comparisons between iTRAQ and spectral counting revealed that 30 of the 37 proteins quantified via iTRAQ exhibited trends similar to those identified by the label-free method. Both proteomic techniques mutually identified 16 proteins that were significantly different between the two groups of hemocytes (p value < 0.05). The presence of V. fischeri in the host light organ influenced the abundance of proteins associated with the cytoskeleton, adhesion, lysosomes, proteolysis, and the innate immune response. These data provide evidence that colonization by V. fischeri alters the hemocyte proteome and reveals proteins that may be important for maintaining host-symbiont specificity.},
}
@article {pmid25014649,
year = {2014},
author = {Chavez-Dozal, AA and Gorman, C and Lostroh, CP and Nishiguchi, MK},
title = {Gene-swapping mediates host specificity among symbiotic bacteria in a beneficial symbiosis.},
journal = {PloS one},
volume = {9},
number = {7},
pages = {e101691},
doi = {10.1371/journal.pone.0101691},
pmid = {25014649},
issn = {1932-6203},
support = {T34 GM007667/GM/NIGMS NIH HHS/United States ; R25GM061222/GM/NIGMS NIH HHS/United States ; GM0007667-34/GM/NIGMS NIH HHS/United States ; 1SC1AI081659-01/AI/NIAID NIH HHS/United States ; 3SC1AI081659-02S1/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Animals ; Decapodiformes/*microbiology ; Genetic Variation/genetics ; Host Specificity/genetics/physiology ; Symbiosis/genetics/*physiology ; },
abstract = {Environmentally acquired beneficial associations are comprised of a wide variety of symbiotic species that vary both genetically and phenotypically, and therefore have differential colonization abilities, even when symbionts are of the same species. Strain variation is common among conspecific hosts, where subtle differences can lead to competitive exclusion between closely related strains. One example where symbiont specificity is observed is in the sepiolid squid-Vibrio mutualism, where competitive dominance exists among V. fischeri isolates due to subtle genetic differences between strains. Although key symbiotic loci are responsible for the establishment of this association, the genetic mechanisms that dictate strain specificity are not fully understood. We examined several symbiotic loci (lux-bioluminescence, pil = pili, and msh-mannose sensitive hemagglutinin) from mutualistic V. fischeri strains isolated from two geographically distinct squid host species (Euprymna tasmanica-Australia and E. scolopes-Hawaii) to determine whether slight genetic differences regulated host specificity. Through colonization studies performed in naïve squid hatchlings from both hosts, we found that all loci examined are important for specificity and host recognition. Complementation of null mutations in non-native V. fischeri with loci from the native V. fischeri caused a gain in fitness, resulting in competitive dominance in the non-native host. The competitive ability of these symbiotic loci depended upon the locus tested and the specific squid species in which colonization was measured. Our results demonstrate that multiple bacterial genetic elements can determine V. fischeri strain specificity between two closely related squid hosts, indicating how important genetic variation is for regulating conspecific beneficial interactions that are acquired from the environment.},
}
@article {pmid24995875,
year = {2014},
author = {McFall-Ngai, MJ},
title = {The importance of microbes in animal development: lessons from the squid-vibrio symbiosis.},
journal = {Annual review of microbiology},
volume = {68},
number = {},
pages = {177-194},
doi = {10.1146/annurev-micro-091313-103654},
pmid = {24995875},
issn = {1545-3251},
mesh = {Animals ; Decapodiformes/*growth & development/*microbiology/physiology ; *Symbiosis ; Vibrio/*physiology ; },
abstract = {Developmental biology is among the many subdisciplines of the life sciences being transformed by our increasing awareness of the role of coevolved microbial symbionts in health and disease. Most symbioses are horizontally acquired, i.e., they begin anew each generation. In such associations, the embryonic period prepares the animal to engage with the coevolved partner(s) with fidelity following birth or hatching. Once interactions are underway, the microbial partners drive maturation of tissues that are either directly associated with or distant from the symbiont populations. Animal alliances often involve complex microbial communities, such as those in the vertebrate gastrointestinal tract. A series of simpler-model systems is providing insight into the basic rules and principles that govern the establishment and maintenance of stable animal-microbe partnerships. This review focuses on what biologists have learned about the developmental trajectory of horizontally acquired symbioses through the study of the binary squid-vibrio model.},
}
@article {pmid24975083,
year = {2014},
author = {He, JY and Chi, CF and Liu, HH},
title = {Identification and analysis of an intracellular Cu/Zn superoxide dismutase from Sepiella maindroni under stress of Vibrio harveyi and Cd2+.},
journal = {Developmental and comparative immunology},
volume = {47},
number = {1},
pages = {1-5},
doi = {10.1016/j.dci.2014.06.010},
pmid = {24975083},
issn = {1879-0089},
mesh = {Animals ; Cadmium/metabolism ; DNA, Complementary ; Hepatopancreas ; Molecular Sequence Data ; Phylogeny ; Sepia/*enzymology/*immunology/microbiology ; Superoxide Dismutase/genetics/immunology/*isolation & purification/metabolism ; Vibrio/*physiology ; },
abstract = {Superoxide dismutases (SODs) are ubiquitous family of metalloenzymes involved in protecting organisms from excess reactive oxygen species damage. In this paper, a novel intracellular Cu/ZnSOD from Sepiella maindroni (designated as SmSOD) was identified and characterized. The full-length cDNA sequence of SmSOD (GenBank accession No. KF908850) was 709 bp containing an open reading frame (ORF) of 459 bp, encoding 153 amino acid residues peptide with predicted pI/MW (6.02/15.75 kDa), a 131 bp-5'- and 116 bp-3'- untranslated region (UTR). BLASTn analysis and phylogenetic relationship strongly suggested that the sequence shared high similarity with known Cu/Zn SODs. Several highly conserved motifs, including two typical Cu/Zn SOD family domains, two conserved Cu-/Zn-binding sites (H-47, H-49, H-64, H-120 for Cu binding, and H-64, H-72, H-81, D-84 for Zn binding) and intracellular disulfide bond (C-58 and C-146), were also identified in SmSOD. Time-dependent mRNA expression of SmSOD in hepatopancreas was recorded by quantitative real-time RT-PCR after Vibrio harveyi injection and Cd(2+) exposure. The results indicated that SmSOD was an acute-phase protein involved in the immune responses against pathogens and biological indicator for metal contaminants in aquatic environment.},
}
@article {pmid24807261,
year = {2014},
author = {Kremer, N and Schwartzman, J and Augustin, R and Zhou, L and Ruby, EG and Hourdez, S and McFall-Ngai, MJ},
title = {The dual nature of haemocyanin in the establishment and persistence of the squid-vibrio symbiosis.},
journal = {Proceedings. Biological sciences},
volume = {281},
number = {1785},
pages = {20140504},
doi = {10.1098/rspb.2014.0504},
pmid = {24807261},
issn = {1471-2954},
support = {OD 011024/OD/NIH HHS/United States ; R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM008505/GM/NIGMS NIH HHS/United States ; AI 50661/AI/NIAID NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*physiology ; Amino Acid Sequence ; Animals ; Decapodiformes/*microbiology/*physiology ; Hawaii ; Hemocyanins/chemistry/*genetics/metabolism ; Immunohistochemistry ; Molecular Sequence Data ; Phylogeny ; Protein Isoforms/chemistry/genetics/metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Sequence Alignment ; *Symbiosis ; },
abstract = {We identified and sequenced from the squid Euprymna scolopes two isoforms of haemocyanin that share the common structural/physiological characteristics of haemocyanin from a closely related cephalopod, Sepia officinalis, including a pronounced Bohr effect. We examined the potential roles for haemocyanin in the animal's symbiosis with the luminous bacterium Vibrio fischeri. Our data demonstrate that, as in other cephalopods, the haemocyanin is primarily synthesized in the gills. It transits through the general circulation into other tissues and is exported into crypt spaces that support the bacterial partner, which requires oxygen for its bioluminescence. We showed that the gradient of pH between the circulating haemolymph and the matrix of the crypt spaces in adult squid favours offloading of oxygen from the haemocyanin to the symbionts. Haemocyanin is also localized to the apical surfaces and associated mucus of a juvenile-specific epithelium on which the symbionts gather, and where their specificity is determined during the recruitment into the association. The haemocyanin has an antimicrobial activity, which may be involved in this enrichment of V. fischeri during symbiont initiation. Taken together, these data provide evidence that the haemocyanin plays a role in shaping two stages of the squid-vibrio partnership.},
}
@article {pmid24802887,
year = {2014},
author = {Heath-Heckman, EA and Gillette, AA and Augustin, R and Gillette, MX and Goldman, WE and McFall-Ngai, MJ},
title = {Shaping the microenvironment: evidence for the influence of a host galaxin on symbiont acquisition and maintenance in the squid-Vibrio symbiosis.},
journal = {Environmental microbiology},
volume = {16},
number = {12},
pages = {3669-3682},
doi = {10.1111/1462-2920.12496},
pmid = {24802887},
issn = {1462-2920},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM007215/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; T-32GM07215/GM/NIGMS NIH HHS/United States ; R01-AI50661/AI/NIAID NIH HHS/United States ; R01-RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/drug effects/growth & development/*physiology ; Animals ; Anti-Bacterial Agents/pharmacology ; Bacteria/drug effects ; Decapodiformes/genetics/*metabolism/*microbiology ; Epithelium/chemistry ; Mucus/chemistry ; Peptides/pharmacology ; Proteins/analysis/chemistry/genetics/*metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; *Symbiosis ; Transcriptome ; },
abstract = {Most bacterial species make transitions between habitats, such as switching from free living to symbiotic niches. We provide evidence that a galaxin protein, EsGal1, of the squid Euprymna scolopes participates in both: (i) selection of the specific partner Vibrio fischeri from the bacterioplankton during symbiosis onset and, (ii) modulation of V. fischeri growth in symbiotic maintenance. We identified two galaxins in transcriptomic databases and showed by quantitative reverse-transcriptase polymerase chain reaction that one (esgal1) was dominant in the light organ. Further, esgal1 expression was upregulated by symbiosis, a response that was partially achieved with exposure to symbiont cell-envelope molecules. Confocal immunocytochemistry of juvenile animals localized EsGal1 to the apical surfaces of light-organ epithelia and surrounding mucus, the environment in which V. fischeri cells aggregate before migration into the organ. Growth assays revealed that one repeat of EsGal1 arrested growth of Gram-positive bacterial cells, which represent the cell type first 'winnowed' during initial selection of the symbiont. The EsGal1-derived peptide also significantly decreased the growth rate of V. fischeri in culture. Further, when animals were exposed to an anti-EsGal1 antibody, symbiont population growth was significantly increased. These data provide a window into how hosts select symbionts from a rich environment and govern their growth in symbiosis.},
}
@article {pmid24648207,
year = {2014},
author = {Koropatnick, T and Goodson, MS and Heath-Heckman, EA and McFall-Ngai, M},
title = {Identifying the cellular mechanisms of symbiont-induced epithelial morphogenesis in the squid-Vibrio association.},
journal = {The Biological bulletin},
volume = {226},
number = {1},
pages = {56-68},
doi = {10.1086/BBLv226n1p56},
pmid = {24648207},
issn = {1939-8697},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM007215/GM/NIGMS NIH HHS/United States ; R01-AI50661/AI/NIAID NIH HHS/United States ; T-32 GM07215/GM/NIGMS NIH HHS/United States ; },
mesh = {Actin Cytoskeleton/metabolism ; Aliivibrio fischeri/*physiology ; Animals ; Apoptosis ; Decapodiformes/*cytology/enzymology/growth & development/*microbiology ; Epithelial Cells/*cytology/enzymology ; Host-Pathogen Interactions/*physiology ; Matrix Metalloproteinases/metabolism ; Microscopy, Confocal ; Morphogenesis/*physiology ; *Symbiosis ; },
abstract = {The symbiotic association between the Hawaiian bobtail squid Euprymna scolopes and the luminous marine bacterium Vibrio fischeri provides a unique opportunity to study epithelial morphogenesis. Shortly after hatching, the squid host harvests bacteria from the seawater using currents created by two elaborate fields of ciliated epithelia on the surface of the juvenile light organ. After light organ colonization, the symbiont population signals the gradual loss of the ciliated epithelia through apoptosis of the cells, which culminates in the complete regression of these tissues. Whereas aspects of this process have been studied at the morphological, biochemical, and molecular levels, no in-depth analysis of the cellular events has been reported. Here we describe the cellular structure of the epithelial field and present evidence that the symbiosis-induced regression occurs in two steps. Using confocal microscopic analyses, we observed an initial epithelial remodeling, which serves to disable the function of the harvesting apparatus, followed by a protracted regression involving actin rearrangements and epithelial cell extrusion. We identified a metal-dependent gelatinolytic activity in the symbiont-induced morphogenic epithelial fields, suggesting the involvement of Zn-dependent matrix metalloproteinase(s) (MMP) in light organ morphogenesis. These data show that the bacterial symbionts not only induce apoptosis of the field, but also change the form, function, and biochemistry of the cells as part of the morphogenic program.},
}
@article {pmid24596155,
year = {2014},
author = {Guillemin, K and Rolig, AS},
title = {A twist in the tail.},
journal = {eLife},
volume = {3},
number = {},
pages = {e02386},
doi = {10.7554/eLife.02386},
pmid = {24596155},
issn = {2050-084X},
mesh = {Aliivibrio fischeri/*metabolism ; Animals ; Decapodiformes/*microbiology ; Flagella/*metabolism ; Lipopolysaccharides/*metabolism ; Vibrio cholerae/*metabolism ; },
abstract = {Lipopolysaccharide molecules released by the bacteria Vibrio fischeri when it rotates its flagella prompts its host, the Hawaiian bobtail squid, to prepare for its arrival.},
}
@article {pmid24596150,
year = {2014},
author = {Brennan, CA and Hunt, JR and Kremer, N and Krasity, BC and Apicella, MA and McFall-Ngai, MJ and Ruby, EG},
title = {A model symbiosis reveals a role for sheathed-flagellum rotation in the release of immunogenic lipopolysaccharide.},
journal = {eLife},
volume = {3},
number = {},
pages = {e01579},
doi = {10.7554/eLife.01579},
pmid = {24596150},
issn = {2050-084X},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM007215/GM/NIGMS NIH HHS/United States ; T32 GM008692/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; T32 AI007414/AI/NIAID NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; OD11024/OD/NIH HHS/United States ; AI50661/AI/NIAID NIH HHS/United States ; T32 AI055397/AI/NIAID NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/immunology/*metabolism/pathogenicity ; Animals ; Decapodiformes/growth & development/immunology/metabolism/*microbiology ; Flagella/immunology/*metabolism ; Genotype ; Host-Pathogen Interactions ; Lipopolysaccharides/immunology/*metabolism ; Morphogenesis ; Mutation ; Phenotype ; Signal Transduction ; Symbiosis ; Vibrio cholerae/genetics/immunology/*metabolism/pathogenicity ; },
abstract = {Bacterial flagella mediate host-microbe interactions through tissue tropism during colonization, as well as by activating immune responses. The flagellar shaft of some bacteria, including several human pathogens, is encased in a membranous sheath of unknown function. While it has been hypothesized that the sheath may allow these bacteria to evade host responses to the immunogenic flagellin subunit, this unusual structural feature has remained an enigma. Here we demonstrate that the rotation of the sheathed flagellum in both the mutualist Vibrio fischeri and the pathogen Vibrio cholerae promotes release of a potent bacteria-derived immunogen, lipopolysaccharide, found in the flagellar sheath. We further present a new role for the flagellar sheath in triggering, rather than circumventing, host immune responses in the model squid-vibrio symbiosis. Such an observation not only has implications for the study of bacterial pathogens with sheathed flagella, but also raises important biophysical questions of sheathed-flagellum function. DOI: http://dx.doi.org/10.7554/eLife.01579.001.},
}
@article {pmid24504482,
year = {2014},
author = {McFall-Ngai, M},
title = {Divining the essence of symbiosis: insights from the squid-vibrio model.},
journal = {PLoS biology},
volume = {12},
number = {2},
pages = {e1001783},
doi = {10.1371/journal.pbio.1001783},
pmid = {24504482},
issn = {1545-7885},
support = {AI50661/AI/NIAID NIH HHS/United States ; },
mesh = {Animals ; Decapodiformes/cytology/*microbiology ; Epithelium/microbiology ; Models, Biological ; *Symbiosis ; Vibrio/*physiology ; },
abstract = {Biology has a big elephant in the room. Researchers are learning that microorganisms are critical for every aspect of the biosphere's health. Even at the scale of our own bodies, we are discovering the unexpected necessity and daunting complexity of our microbial partners. How can we gain an understanding of the form and function of these "ecosystems" that are an individual animal? This essay explores how development of experimental model systems reveals basic principles that underpin the essence of symbiosis and, more specifically, how one symbiosis, the squid-vibrio association, provides insight into the persistent microbial colonization of animal epithelial surfaces.},
}
@article {pmid24402368,
year = {2014},
author = {Soto, W and Rivera, FM and Nishiguchi, MK},
title = {Ecological diversification of Vibrio fischeri serially passaged for 500 generations in novel squid host Euprymna tasmanica.},
journal = {Microbial ecology},
volume = {67},
number = {3},
pages = {700-721},
doi = {10.1007/s00248-013-0356-3},
pmid = {24402368},
issn = {1432-184X},
support = {R25 GM061222/GM/NIGMS NIH HHS/United States ; T34 GM007667/GM/NIGMS NIH HHS/United States ; 1SC1AI081659/AI/NIAID NIH HHS/United States ; R25GM061222/GM/NIGMS NIH HHS/United States ; GM07667-35/GM/NIGMS NIH HHS/United States ; 3SC1AI081659-02S1/AI/NIAID NIH HHS/United States ; SC1 AI081659/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*physiology ; Animals ; Biofilms ; *Biological Evolution ; Carbon/*metabolism ; Decapodiformes/*microbiology ; Luminescent Measurements ; Selection, Genetic ; },
abstract = {Vibrio fischeri isolated from Euprymna scolopes (Cephalopoda: Sepiolidae) was used to create 24 lines that were serially passaged through the non-native host Euprymna tasmanica for 500 generations. These derived lines were characterized for biofilm formation, swarming motility, carbon source utilization, and in vitro bioluminescence. Phenotypic assays were compared between "ES" (E. scolopes) and "ET" (E. tasmanica) V. fischeri wild isolates to determine if convergent evolution was apparent between E. tasmanica evolved lines and ET V. fischeri. Ecological diversification was observed in utilization of most carbon sources examined. Convergent evolution was evident in motility, biofilm formation, and select carbon sources displaying hyperpolymorphic usage in V. fischeri. Convergence in bioluminescence (a 2.5-fold increase in brightness) was collectively evident in the derived lines relative to the ancestor. However, dramatic changes in other properties--time points and cell densities of first light emission and maximal light output and emergence of a lag phase in growth curves of derived lines--suggest that increased light intensity per se was not the only important factor. Convergent evolution implies that gnotobiotic squid light organs subject colonizing V. fischeri to similar selection pressures. Adaptation to novel hosts appears to involve flexible microbial metabolism, establishment of biofilm and swarmer V. fischeri ecotypes, and complex changes in bioluminescence. Our data demonstrate that numerous alternate fitness optima or peaks are available to V. fischeri in host adaptive landscapes, where novel host squids serve as habitat islands. Thus, V. fischeri founder flushes occur during the initiation of light organ colonization that ultimately trigger founder effect diversification.},
}
@article {pmid24348467,
year = {2013},
author = {Norsworthy, AN and Visick, KL},
title = {Gimme shelter: how Vibrio fischeri successfully navigates an animal's multiple environments.},
journal = {Frontiers in microbiology},
volume = {4},
number = {},
pages = {356},
doi = {10.3389/fmicb.2013.00356},
pmid = {24348467},
issn = {1664-302X},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; },
abstract = {Bacteria successfully colonize distinct niches because they can sense and appropriately respond to a variety of environmental signals. Of particular interest is how a bacterium negotiates the multiple, complex environments posed during successful infection of an animal host. One tractable model system to study how a bacterium manages a host's multiple environments is the symbiotic relationship between the marine bacterium, Vibrio fischeri, and its squid host, Euprymna scolopes. V. fischeri encounters many different host surroundings ranging from initial contact with the squid to ultimate colonization of a specialized organ known as the light organ. For example, upon recognition of the squid, V. fischeri forms a biofilm aggregate outside the light organ that is required for efficient colonization. The bacteria then disperse from this biofilm to enter the organ, where they are exposed to nitric oxide, a molecule that can act as both a signal and an antimicrobial. After successfully managing this potentially hostile environment, V. fischeri cells finally establish their niche in the deep crypts of the light organ where the bacteria bioluminesce in a pheromone-dependent fashion, a phenotype that E. scolopes utilizes for anti-predation purposes. The mechanism by which V. fischeri manages these environments to outcompete all other bacterial species for colonization of E. scolopes is an important and intriguing question that will permit valuable insights into how a bacterium successfully associates with a host. This review focuses on specific molecular pathways that allow V. fischeri to establish this exquisite bacteria-host interaction.},
}
@article {pmid24191970,
year = {2014},
author = {Studer, SV and Schwartzman, JA and Ho, JS and Geske, GD and Blackwell, HE and Ruby, EG},
title = {Non-native acylated homoserine lactones reveal that LuxIR quorum sensing promotes symbiont stability.},
journal = {Environmental microbiology},
volume = {16},
number = {8},
pages = {2623-2634},
doi = {10.1111/1462-2920.12322},
pmid = {24191970},
issn = {1462-2920},
support = {R01 GM109403/GM/NIGMS NIH HHS/United States ; R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM008505/GM/NIGMS NIH HHS/United States ; T32 GM007215/GM/NIGMS NIH HHS/United States ; RR12294/OD11024/OD/NIH HHS/United States ; T32 GM07215/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01 GM099507/GM/NIGMS NIH HHS/United States ; AI050661/AI/NIAID NIH HHS/United States ; R01 AI063326/AI/NIAID NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; },
mesh = {4-Butyrolactone/*analogs & derivatives/metabolism ; Aliivibrio fischeri/*genetics/metabolism ; Animals ; Bacterial Proteins/*genetics/metabolism ; Decapodiformes/microbiology ; *Gene Expression Regulation, Bacterial ; Luminescence ; Quorum Sensing/*genetics ; Repressor Proteins/*genetics/metabolism ; Symbiosis/*genetics ; Time Factors ; Trans-Activators/*genetics/metabolism ; Transcription Factors/*genetics/metabolism ; },
abstract = {Quorum sensing, a group behaviour coordinated by a diffusible pheromone signal and a cognate receptor, is typical of bacteria that form symbioses with plants and animals. LuxIR-type N-acyl L-homoserine (AHL) quorum sensing is common in Gram-negative Proteobacteria, and many members of this group have additional quorum-sensing networks. The bioluminescent symbiont Vibrio fischeri encodes two AHL signal synthases: AinS and LuxI. AinS-dependent quorum sensing converges with LuxI-dependent quorum sensing at the LuxR regulatory element. Both AinS- and LuxI-mediated signalling are required for efficient and persistent colonization of the squid host, Euprymna scolopes. The basis of the mutualism is symbiont bioluminescence, which is regulated by both LuxI- and AinS-dependent quorum sensing, and is essential for maintaining a colonization of the host. Here, we used chemical and genetic approaches to probe the dynamics of LuxI- and AinS-mediated regulation of bioluminescence during symbiosis. We demonstrate that both native AHLs and non-native AHL analogues can be used to non-invasively and specifically modulate induction of symbiotic bioluminescence via LuxI-dependent quorum sensing. Our data suggest that the first day of colonization, during which symbiont bioluminescence is induced by LuxIR, is a critical period that determines the stability of the V. fischeri population once symbiosis is established.},
}
@article {pmid24157521,
year = {2014},
author = {Peyer, SM and Pankey, MS and Oakley, TH and McFall-Ngai, MJ},
title = {Eye-specification genes in the bacterial light organ of the bobtail squid Euprymna scolopes, and their expression in response to symbiont cues.},
journal = {Mechanisms of development},
volume = {131},
number = {},
pages = {111-126},
doi = {10.1016/j.mod.2013.09.004},
pmid = {24157521},
issn = {1872-6356},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; AI-50661/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/metabolism ; Animals ; Biological Evolution ; Decapodiformes/embryology/genetics/*microbiology/physiology ; Embryo, Nonmammalian ; Embryonic Development/*genetics ; Eye/*growth & development ; Light ; Symbiosis/*genetics ; },
abstract = {The squid Euprymna scolopes has evolved independent sets of tissues capable of light detection, including a complex eye and a photophore or 'light organ', which houses the luminous bacterial symbiont Vibrio fischeri. As the eye and light organ originate from different embryonic tissues, we examined whether the eye-specification genes, pax6, eya, six, and dac, are shared by these two organs, and if so, whether they are regulated in the light organ by symbiosis. We obtained sequences of the four genes with PCR, confirmed orthology with phylogenetic analysis, and determined that each was expressed in the eye and light organ. With in situ hybridization (ISH), we localized the gene transcripts in developing embryos, comparing the patterns of expression in the two organs. The four transcripts localized to similar tissues, including those associated with the visual system ∼1/4 into embryogenesis (Naef stage 18) and the light organ ∼3/4 into embryogenesis (Naef stage 26). We used ISH and quantitative real-time PCR to examine transcript expression and differential regulation in postembryonic light organs in response to the following colonization conditions: wild-type, luminescent V. fischeri; a mutant strain defective in light production; and as a control, no symbiont. In ISH experiments light organs showed down regulation of the pax6, eya, and six transcripts in response to wild-type V. fischeri. Mutant strains also induced down regulation of the pax6 and eya transcripts, but not of the six transcript. Thus, luminescence was required for down regulation of the six transcript. We discuss these results in the context of symbiont-induced light-organ development. Our study indicates that the eye-specification genes are expressed in light-interacting tissues independent of their embryonic origin and are capable of responding to bacterial cues. These results offer evidence for evolutionary tinkering or the recruitment of eye development genes for use in a light-sensing photophore.},
}
@article {pmid24155650,
year = {2013},
author = {Nakaguchi, Y},
title = {Contamination by Vibrio parahaemolyticus and Its Virulent Strains in Seafood Marketed in Thailand, Vietnam, Malaysia, and Indonesia.},
journal = {Tropical medicine and health},
volume = {41},
number = {3},
pages = {95-102},
doi = {10.2149/tmh.2011-06},
pmid = {24155650},
issn = {1348-8945},
abstract = {Infections by virulent strains of Vibrio parahaemolyticus are frequently reported in Southeast Asia. This is due to the frequent seafood contamination by virulent strains. In this study conducted from 2008 to 2011, seafood like fish, shrimp, squid, crab, and molluscan shellfish were purchased from provinces in Thailand and three Southeast Asian countries and examined for the prevalence of three genetic markers of V. parahaemolyticus (species-specific gene: toxR gene, virulence genes: tdh and trh genes). An enrichment culture of seafood was examined for these markers using PCR methods. Molluscan shellfish showed a high frequency of contamination in Thailand. The shellfish harvested from the Gulf of Thailand were significantly more contaminated with virulence genes than those from the Andaman Sea. The seafood purchased from three Southeast Asian countries was positive for the three markers of V. parahaemolytcus at differing frequencies. The virulence markers (tdh and trh markers) were frequently detected in molluscan shellfish from Vietnam (17.9 and 8.0%, respectively), Malaysia (11.1 and 16.7%), and Indonesia (9.1 and 13.6%). These data suggest that the molluscan shellfish sold in Southeast Asian markets are highly contaminated with virulent strains of V. parahaemolyticus.},
}
@article {pmid24118200,
year = {2014},
author = {Koch, EJ and Miyashiro, T and McFall-Ngai, MJ and Ruby, EG},
title = {Features governing symbiont persistence in the squid-vibrio association.},
journal = {Molecular ecology},
volume = {23},
number = {6},
pages = {1624-1634},
doi = {10.1111/mec.12474},
pmid = {24118200},
issn = {1365-294X},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; R00 GM097032/GM/NIGMS NIH HHS/United States ; K99 GM097032/GM/NIGMS NIH HHS/United States ; GM097032/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01 GM099507/GM/NIGMS NIH HHS/United States ; GM099507/GM/NIGMS NIH HHS/United States ; OD11024/OD/NIH HHS/United States ; AI50661/AI/NIAID NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Animal Structures/growth & development/microbiology ; Animals ; Decapodiformes/growth & development/*microbiology ; Light ; *Symbiosis ; },
abstract = {Experimental studies of the interaction between host and symbiont in a maturing symbiotic organ have presented a challenge for most animal-bacterial associations. Advances in the rearing of the host squid Euprymna scolopes have enabled us to explore the relationship between a defect in symbiont light production and late-stage development (e.g. symbiont persistence and tissue morphogenesis) by experimental colonization with specific strains of the symbiont Vibrio fischeri. During the first 4 weeks postinoculation of juvenile squid, the population of wild-type V. fischeri increased 100-fold; in contrast, a strain defective in light production (Δlux) colonized normally the first day, but exhibited an exponential decline to undetectable levels over subsequent weeks. Co-colonization of organs by both strains affected neither the trajectory of colonization by wild type nor the decline of Δlux levels. Uninfected animals retained the ability to be colonized for at least 2 weeks posthatch. However, once colonized by the wild-type strain for 5 days, a subsequent experimentally induced loss of the symbionts could not be followed by a successful recolonization, indicating the host's entry into a refractory state. However, animals colonized by the Δlux before the loss of their symbionts were receptive to recolonization. Analyses of animals colonized with either a wild-type or a Δlux strain revealed slight, if any, differences in the developmental regression of the ciliated light-organ tissues that facilitate the colonization process. Thus, some other feature(s) of the Δlux strain's defect also may be responsible for its inability to persist, and its failure to induce a refractory state in the host.},
}
@article {pmid24092734,
year = {2013},
author = {Cohen, J},
title = {Great presenters: lighting up the auditorium.},
journal = {Science (New York, N.Y.)},
volume = {342},
number = {6154},
pages = {78},
doi = {10.1126/science.342.6154.78},
pmid = {24092734},
issn = {1095-9203},
mesh = {Animals ; Bacteria/*chemistry ; Decapodiformes/*microbiology ; *Luminescence ; *Quorum Sensing ; Symbiosis ; },
}
@article {pmid23979430,
year = {2013},
author = {Kåhrström, CT},
title = {Symbiosis: breaking the ice with your host.},
journal = {Nature reviews. Microbiology},
volume = {11},
number = {10},
pages = {663},
doi = {10.1038/nrmicro3114},
pmid = {23979430},
issn = {1740-1534},
mesh = {Aliivibrio fischeri/*physiology ; Animals ; Decapodiformes/*microbiology/*physiology ; *Symbiosis ; },
}
@article {pmid23965960,
year = {2013},
author = {Verma, SC and Miyashiro, T},
title = {Quorum sensing in the squid-Vibrio symbiosis.},
journal = {International journal of molecular sciences},
volume = {14},
number = {8},
pages = {16386-16401},
doi = {10.3390/ijms140816386},
pmid = {23965960},
issn = {1422-0067},
support = {R00 GM097032/GM/NIGMS NIH HHS/United States ; 4R00GM097032/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Animals ; Bacterial Proteins/physiology ; Decapodiformes/*microbiology ; *Quorum Sensing ; Signal Transduction ; Symbiosis ; },
abstract = {Quorum sensing is an intercellular form of communication that bacteria use to coordinate group behaviors such as biofilm formation and the production of antibiotics and virulence factors. The term quorum sensing was originally coined to describe the mechanism underlying the onset of luminescence production in cultures of the marine bacterium Vibrio fischeri. Luminescence and, more generally, quorum sensing are important for V. fischeri to form a mutualistic symbiosis with the Hawaiian bobtail squid, Euprymna scolopes. The symbiosis is established when V. fischeri cells migrate via flagella-based motility from the surrounding seawater into a specialized structure injuvenile squid called the light organ. The cells grow to high cell densities within the light organ where the infection persists over the lifetime of the animal. A hallmark of a successful symbiosis is the luminescence produced by V. fischeri that camouflages the squid at night by eliminating its shadow within the water column. While the regulatory networks governing quorum sensing are critical for properly regulating V. fischeri luminescence within the squid light organ, they also regulate luminescence-independent processes during symbiosis. In this review, we discuss the quorum-sensing network of V. fischeri and highlight its impact at various stages during host colonization.},
}
@article {pmid23954157,
year = {2013},
author = {Kremer, N and Philipp, EE and Carpentier, MC and Brennan, CA and Kraemer, L and Altura, MA and Augustin, R and Häsler, R and Heath-Heckman, EA and Peyer, SM and Schwartzman, J and Rader, BA and Ruby, EG and Rosenstiel, P and McFall-Ngai, MJ},
title = {Initial symbiont contact orchestrates host-organ-wide transcriptional changes that prime tissue colonization.},
journal = {Cell host & microbe},
volume = {14},
number = {2},
pages = {183-194},
doi = {10.1016/j.chom.2013.07.006},
pmid = {23954157},
issn = {1934-6069},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM007215/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; AI50661/AI/NIAID NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Animals ; Chemotactic Factors/metabolism ; Chitin/metabolism ; Chitinases/metabolism ; Decapodiformes/*microbiology/*physiology ; Disaccharides/metabolism ; Gene Expression Profiling ; Gene Expression Regulation ; Molecular Sequence Data ; Mucus/metabolism ; Sequence Analysis, DNA ; *Symbiosis ; },
abstract = {Upon transit to colonization sites, bacteria often experience critical priming that prepares them for subsequent, specific interactions with the host; however, the underlying mechanisms are poorly described. During initiation of the symbiosis between the bacterium Vibrio fischeri and its squid host, which can be observed directly and in real time, approximately five V. fischeri cells aggregate along the mucociliary membranes of a superficial epithelium prior to entering host tissues. Here, we show that these few early host-associated symbionts specifically induce robust changes in host gene expression that are critical to subsequent colonization steps. This exquisitely sensitive response to the host's specific symbiotic partner includes the upregulation of a host endochitinase, whose activity hydrolyzes polymeric chitin in the mucus into chitobiose, thereby priming the symbiont and also producing a chemoattractant gradient that promotes V. fischeri migration into host tissues. Thus, the host responds transcriptionally upon initial symbiont contact, which facilitates subsequent colonization.},
}
@article {pmid23954151,
year = {2013},
author = {Wernegreen, JJ},
title = {First impressions in a glowing host-microbe partnership.},
journal = {Cell host & microbe},
volume = {14},
number = {2},
pages = {121-123},
doi = {10.1016/j.chom.2013.07.015},
pmid = {23954151},
issn = {1934-6069},
support = {R01 GM062626/GM/NIGMS NIH HHS/United States ; R01GM062626/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Animals ; Decapodiformes/*microbiology/*physiology ; *Symbiosis ; },
abstract = {Despite the clear significance of beneficial animal-microbe associations, mechanisms underlying their initiation and establishment are rarely understood. In this issue of Cell Host & Microbe, Kremer et al. (2013) reveal that first contact within the squid-vibrio symbiosis triggers profound molecular and chemical changes that are crucial for bacterial colonization.},
}
@article {pmid23907990,
year = {2013},
author = {Brennan, CA and Mandel, MJ and Gyllborg, MC and Thomasgard, KA and Ruby, EG},
title = {Genetic determinants of swimming motility in the squid light-organ symbiont Vibrio fischeri.},
journal = {MicrobiologyOpen},
volume = {2},
number = {4},
pages = {576-594},
doi = {10.1002/mbo3.96},
pmid = {23907990},
issn = {2045-8827},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM007215/GM/NIGMS NIH HHS/United States ; T32 GM07215/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; T32 AI055397/AI/NIAID NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; T32 AI55397/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*physiology ; Animal Structures/microbiology ; Animals ; Bacteriological Techniques ; Chemotaxis ; Culture Media/chemistry ; Decapodiformes/*microbiology ; Flagella/genetics/physiology ; *Genes, Bacterial ; *Locomotion ; Mutagenesis, Insertional ; Mutation ; *Symbiosis ; },
abstract = {Bacterial flagellar motility is a complex cellular behavior required for the colonization of the light-emitting organ of the Hawaiian bobtail squid, Euprymna scolopes, by the beneficial bioluminescent symbiont Vibrio fischeri. We characterized the basis of this behavior by performing (i) a forward genetic screen to identify mutants defective in soft-agar motility, as well as (ii) a transcriptional analysis to determine the genes that are expressed downstream of the flagellar master regulator FlrA. Mutants with severe defects in soft-agar motility were identified due to insertions in genes with putative roles in flagellar motility and in genes that were unexpected, including those predicted to encode hypothetical proteins and cell division-related proteins. Analysis of mutants for their ability to enter into a productive symbiosis indicated that flagellar motility mutants are deficient, while chemotaxis mutants are able to colonize a subset of juvenile squid to light-producing levels. Thirty-three genes required for normal motility in soft agar were also downregulated in the absence of FlrA, suggesting they belong to the flagellar regulon of V. fischeri. Mutagenesis of putative paralogs of the flagellar motility genes motA, motB, and fliL revealed that motA1, motB1, and both fliL1 and fliL2, but not motA2 and motB2, likely contribute to soft-agar motility. Using these complementary approaches, we have characterized the genetic basis of flagellar motility in V. fischeri and furthered our understanding of the roles of flagellar motility and chemotaxis in colonization of the juvenile squid, including identifying 11 novel mutants unable to enter into a productive light-organ symbiosis.},
}
@article {pmid23819708,
year = {2013},
author = {Altura, MA and Heath-Heckman, EA and Gillette, A and Kremer, N and Krachler, AM and Brennan, C and Ruby, EG and Orth, K and McFall-Ngai, MJ},
title = {The first engagement of partners in the Euprymna scolopes-Vibrio fischeri symbiosis is a two-step process initiated by a few environmental symbiont cells.},
journal = {Environmental microbiology},
volume = {15},
number = {11},
pages = {2937-2950},
doi = {10.1111/1462-2920.12179},
pmid = {23819708},
issn = {1462-2920},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM007215/GM/NIGMS NIH HHS/United States ; NIH-NRSA AI55397/AI/NIAID NIH HHS/United States ; NIH RR 12294/RR/NCRR NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; NIH AI 50661/AI/NIAID NIH HHS/United States ; T32 AI055397/AI/NIAID NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*pathogenicity ; Animals ; Bacterial Adhesion/genetics/*physiology ; Bacterial Proteins/metabolism ; Cilia/*microbiology ; Decapodiformes/*microbiology ; Environment ; Epithelium/microbiology ; Hemocytes/physiology ; Host-Pathogen Interactions/genetics ; Light ; Mucous Membrane/microbiology ; Polysaccharides, Bacterial/genetics ; Symbiosis/*physiology ; },
abstract = {We studied the Euprymna scolopes-Vibrio fischeri symbiosis to characterize, in vivo and in real time, the transition between the bacterial partner's free-living and symbiotic life styles. Previous studies using high inocula demonstrated that environmental V. fischeri cells aggregate during a 3 h period in host-shed mucus along the light organ's superficial ciliated epithelia. Under lower inoculum conditions, similar to the levels of symbiont cells in the environment, this interaction induces haemocyte trafficking into these tissues. Here, in experiments simulating natural conditions, microscopy revealed that at 3 h following first exposure, only ∼ 5 V. fischeri cells aggregated on the organ surface. These cells associated with host cilia and induced haemocyte trafficking. Symbiont viability was essential and mutants defective in symbiosis initiation and/or production of certain surface features, including the Mam7 protein, which is implicated in host cell attachment of V. cholerae, associated normally with host cilia. Studies with exopolysaccharide mutants, which are defective in aggregation, suggest a two-step process of V. fischeri cell engagement: association with host cilia followed by aggregation, i.e. host cell-symbiont interaction with subsequent symbiont-symbiont cell interaction. Taken together, these data provide a new model of early partner engagement, a complex model of host-symbiont interaction with exquisite sensitivity.},
}
@article {pmid23744921,
year = {2013},
author = {Pennisi, E},
title = {Mysteries of development. How do microbes shape animal development?.},
journal = {Science (New York, N.Y.)},
volume = {340},
number = {6137},
pages = {1159-1160},
doi = {10.1126/science.340.6137.1159},
pmid = {23744921},
issn = {1095-9203},
mesh = {Animals ; *Bacterial Physiological Phenomena ; Bacteroides fragilis/metabolism ; Brain/growth & development ; Cell Differentiation/genetics ; Decapodiformes/growth & development/microbiology ; Gastrointestinal Tract/microbiology ; Germ-Free Life ; *Growth and Development ; Metagenome/*physiology ; Mice ; Symbiosis ; },
}
@article {pmid23604049,
year = {2013},
author = {Kåhrström, CT},
title = {Symbiosis: Bacteria seize control of the clock.},
journal = {Nature reviews. Microbiology},
volume = {11},
number = {6},
pages = {362},
doi = {10.1038/nrmicro3027},
pmid = {23604049},
issn = {1740-1534},
mesh = {Aliivibrio fischeri/*physiology ; Animals ; Cryptochromes/*biosynthesis ; Decapodiformes/*enzymology/*microbiology ; Gene Expression Regulation/*radiation effects ; *Luminescence ; *Symbiosis ; },
}
@article {pmid23592793,
year = {2013},
author = {Kostic, AD and Howitt, MR and Garrett, WS},
title = {Exploring host-microbiota interactions in animal models and humans.},
journal = {Genes & development},
volume = {27},
number = {7},
pages = {701-718},
doi = {10.1101/gad.212522.112},
pmid = {23592793},
issn = {1549-5477},
support = {R01CA154426/CA/NCI NIH HHS/United States ; AI078942/AI/NIAID NIH HHS/United States ; R01 DK092405/DK/NIDDK NIH HHS/United States ; GM099531/GM/NIGMS NIH HHS/United States ; R01DK092405/DK/NIDDK NIH HHS/United States ; K08 AI078942/AI/NIAID NIH HHS/United States ; R01 CA154426/CA/NCI NIH HHS/United States ; F32DK098826/DK/NIDDK NIH HHS/United States ; R01 GM099537/GM/NIGMS NIH HHS/United States ; F32 DK098826/DK/NIDDK NIH HHS/United States ; },
mesh = {Animals ; Bacterial Physiological Phenomena ; Biological Evolution ; Computational Biology ; Gastrointestinal Tract/microbiology ; Humans ; Metagenome/genetics/*physiology ; *Symbiosis ; },
abstract = {The animal and bacterial kingdoms have coevolved and coadapted in response to environmental selective pressures over hundreds of millions of years. The meta'omics revolution in both sequencing and its analytic pipelines is fostering an explosion of interest in how the gut microbiome impacts physiology and propensity to disease. Gut microbiome studies are inherently interdisciplinary, drawing on approaches and technical skill sets from the biomedical sciences, ecology, and computational biology. Central to unraveling the complex biology of environment, genetics, and microbiome interaction in human health and disease is a deeper understanding of the symbiosis between animals and bacteria. Experimental model systems, including mice, fish, insects, and the Hawaiian bobtail squid, continue to provide critical insight into how host-microbiota homeostasis is constructed and maintained. Here we consider how model systems are influencing current understanding of host-microbiota interactions and explore recent human microbiome studies.},
}
@article {pmid23555890,
year = {2013},
author = {Morris, AR and Visick, KL},
title = {Inhibition of SypG-induced biofilms and host colonization by the negative regulator SypE in Vibrio fischeri.},
journal = {PloS one},
volume = {8},
number = {3},
pages = {e60076},
doi = {10.1371/journal.pone.0060076},
pmid = {23555890},
issn = {1932-6203},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*metabolism/*physiology ; Animals ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Decapodiformes/*microbiology ; Gene Expression Regulation, Bacterial/genetics/physiology ; },
abstract = {Vibrio fischeri produces a specific biofilm to promote colonization of its eukaryotic host, the squid Euprymna scolopes. Formation of this biofilm is induced by the sensor kinase RscS, which functions upstream of the response regulator SypG to regulate transcription of the symbiosis polysaccharide (syp) locus. Biofilm formation is also controlled by SypE, a multi-domain response regulator that consists of a central regulatory receiver (REC) domain flanked by an N-terminal serine kinase domain and a C-terminal serine phosphatase domain. SypE permits biofilm formation under rscS overexpression conditions, but inhibits biofilms induced by overexpression of sypG. We previously investigated the function of SypE in controlling biofilm formation induced by RscS. Here, we examined the molecular mechanism by which SypE naturally inhibits SypG-induced biofilms. We found that SypE's N-terminal kinase domain was both required and sufficient to inhibit SypG-induced biofilms. This effect did not occur at the level of syp transcription. Instead, under sypG-overexpressing conditions, SypE inhibited biofilms by promoting the phosphorylation of another syp regulator, SypA, a putative anti-sigma factor antagonist. Inhibition by SypE of SypG-induced biofilm formation could be overcome by the expression of a non-phosphorylatable SypA mutant, indicating that SypE functions primarily if not exclusively to control SypA activity via phosphorylation. Finally, the presence of SypE was detrimental to colonization under sypG-overexpressing conditions, as cells deleted for sypE outcompeted wild-type cells for colonization when both strains overexpressed sypG. These results provide further evidence that biofilm formation is critical to symbiotic colonization, and support a model in which SypE naturally functions to restrict biofilm formation, and thus host colonization, to the appropriate environmental conditions.},
}
@article {pmid23549919,
year = {2013},
author = {Heath-Heckman, EA and Peyer, SM and Whistler, CA and Apicella, MA and Goldman, WE and McFall-Ngai, MJ},
title = {Bacterial bioluminescence regulates expression of a host cryptochrome gene in the squid-Vibrio symbiosis.},
journal = {mBio},
volume = {4},
number = {2},
pages = {},
doi = {10.1128/mBio.00167-13},
pmid = {23549919},
issn = {2150-7511},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM007215/GM/NIGMS NIH HHS/United States ; P30 ES005605/ES/NIEHS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; R01-AI50661/AI/NIAID NIH HHS/United States ; R01-RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/metabolism/*physiology ; Animals ; Cryptochromes/*biosynthesis ; Decapodiformes/*enzymology/genetics/*microbiology ; Gene Expression Regulation/*radiation effects ; *Luminescence ; *Symbiosis ; },
abstract = {The symbiosis between the squid Euprymna scolopes and its luminous symbiont, Vibrio fischeri, is characterized by daily transcriptional rhythms in both partners and daily fluctuations in symbiont luminescence. In this study, we sought to determine whether symbionts affect host transcriptional rhythms. We identified two transcripts in host tissues (E. scolopes cry1 [escry1] and escry2) that encode cryptochromes, proteins that influence circadian rhythms in other systems. Both genes cycled daily in the head of the squid, with a pattern similar to that of other animals, in which expression of certain cry genes is entrained by environmental light. In contrast, escry1 expression cycled in the symbiont-colonized light organ with 8-fold upregulation coincident with the rhythms of bacterial luminescence, which are offset from the day/night light regime. Colonization of the juvenile light organ by symbionts was required for induction of escry1 cycling. Further, analysis with a mutant strain defective in light production showed that symbiont luminescence is essential for cycling of escry1; this defect could be complemented by presentation of exogenous blue light. However, blue-light exposure alone did not induce cycling in nonsymbiotic animals, but addition of molecules of the symbiont cell envelope to light-exposed animals did recover significant cycling activity, showing that light acts in synergy with other symbiont features to induce cycling. While symbiont luminescence may be a character specific to rhythms of the squid-vibrio association, resident microbial partners could similarly influence well-documented daily rhythms in other systems, such as the mammalian gut.},
}
@article {pmid23461521,
year = {2013},
author = {Petrun, B and Lostroh, CP},
title = {Vibrio fischeri exhibit the growth advantage in stationary-phase phenotype.},
journal = {Canadian journal of microbiology},
volume = {59},
number = {2},
pages = {130-135},
doi = {10.1139/cjm-2012-0439},
pmid = {23461521},
issn = {1480-3275},
mesh = {Aliivibrio fischeri/*growth & development ; Phenotype ; Symbiosis/physiology ; },
abstract = {Vibrio fischeri are bioluminescent marine bacteria that can be isolated from their symbiotic animal partners or from ocean water. A V. fischeri population increases exponentially inside the light organ of the Hawaiian bobtail squid (Euprymna scolopes) while the host is quiescent during the day. This bacterial light organ population reaches stationary phase and then remains high during the night, when the squid use bacterial bioluminescence as a counter-predation strategy. At dawn, host squid release 90%-95% of the light organ contents into the ocean water prior to burying in the sand for the day. As the squid sleeps, the cycle of bacterial population growth in the light organ begins again. These V. fischeri cells that are vented into the ocean must persist under typical marine low nutrient conditions until they encounter another opportunity to colonize a host. We hypothesized that because V. fischeri regularly encounter cycles of feast and famine in nature, they would exhibit the growth advantage in stationary phase (GASP) phenotype. We found that older V. fischeri cells exhibit a Class 2 GASP response in which old cells increase dramatically in frequency while the population of young V. fischeri cells remains almost constant during co-incubation.},
}
@article {pmid23439280,
year = {2013},
author = {Foster, JS and Khodadad, CL and Ahrendt, SR and Parrish, ML},
title = {Impact of simulated microgravity on the normal developmental time line of an animal-bacteria symbiosis.},
journal = {Scientific reports},
volume = {3},
number = {},
pages = {1340},
doi = {10.1038/srep01340},
pmid = {23439280},
issn = {2045-2322},
mesh = {Aliivibrio fischeri/growth & development/*physiology ; Animals ; Apoptosis ; Decapodiformes/*microbiology ; Female ; Hemocytes ; Luminescence ; Models, Biological ; Polysaccharides, Bacterial/immunology ; *Symbiosis ; *Weightlessness Simulation ; },
abstract = {The microgravity environment during space flight imposes numerous adverse effects on animal and microbial physiology. It is unclear, however, how microgravity impacts those cellular interactions between mutualistic microbes and their hosts. Here, we used the symbiosis between the host squid Euprymna scolopes and its luminescent bacterium Vibrio fischeri as a model system. We examined the impact of simulated microgravity on the timeline of bacteria-induced development in the host light organ, the site of the symbiosis. To simulate the microgravity environment, host squid and symbiosis-competent bacteria were incubated together in high-aspect ratio rotating wall vessel bioreactors and examined throughout the early stages of the bacteria-induced morphogenesis. The host innate immune response was suppressed under simulated microgravity; however, there was an acceleration of bacteria-induced apoptosis and regression in the host tissues. These results suggest that the space flight environment may alter the cellular interactions between animal hosts and their natural healthy microbiome.},
}
@article {pmid23377934,
year = {2013},
author = {Lyell, NL and Stabb, EV},
title = {Symbiotic characterization of Vibrio fischeri ES114 mutants that display enhanced luminescence in culture.},
journal = {Applied and environmental microbiology},
volume = {79},
number = {7},
pages = {2480-2483},
doi = {10.1128/AEM.03111-12},
pmid = {23377934},
issn = {1098-5336},
mesh = {Aliivibrio fischeri/genetics/*physiology ; Animals ; Decapodiformes/*microbiology ; *Luminescence ; Mutation ; *Symbiosis ; },
abstract = {Vibrio fischeri ES114 is a bioluminescent symbiont of the squid Euprymna scolopes. Like most isolates from E. scolopes, ES114 produces only dim luminescence outside the host, even in dense cultures. We previously identified mutants with brighter luminescence, and here we report their symbiotic phenotypes, providing insights into the host environment.},
}
@article {pmid23315744,
year = {2013},
author = {Brennan, CA and DeLoney-Marino, CR and Mandel, MJ},
title = {Chemoreceptor VfcA mediates amino acid chemotaxis in Vibrio fischeri.},
journal = {Applied and environmental microbiology},
volume = {79},
number = {6},
pages = {1889-1896},
doi = {10.1128/AEM.03794-12},
pmid = {23315744},
issn = {1098-5336},
support = {R01 OD011024/OD/NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Amino Acids/*metabolism ; Bacterial Proteins/*metabolism ; *Chemotaxis ; DNA Transposable Elements ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Genetic Complementation Test ; Locomotion ; Mutagenesis, Insertional ; *Signal Transduction ; },
abstract = {Flagellar motility and chemotaxis by Vibrio fischeri are important behaviors mediating the colonization of its mutualistic host, the Hawaiian bobtail squid. However, none of the 43 putative methyl-accepting chemotaxis proteins (MCPs) encoded in the V. fischeri genome has been previously characterized. Using both an available transposon mutant collection and directed mutagenesis, we isolated mutants for 19 of these genes, and screened them for altered chemotaxis to six previously identified chemoattractants. Only one mutant was defective in responding to any of the tested compounds; the disrupted gene was thus named vfcA (Vibrio fischeri chemoreceptor A; locus tag VF_0777). In soft-agar plates, mutants disrupted in vfcA did not exhibit the serine-sensing chemotactic ring, and the pattern of migration in the mutant was not affected by the addition of exogenous serine. Using a capillary chemotaxis assay, we showed that, unlike wild-type V. fischeri, the vfcA mutant did not undergo chemotaxis toward serine and that expression of vfcA on a plasmid in the mutant was sufficient to restore the behavior. In addition to serine, we demonstrated that alanine, cysteine, and threonine are strong attractants for wild-type V. fischeri and that the attraction is also mediated by VfcA. This study thus provides the first insights into how V. fischeri integrates information from one of its 43 MCPs to respond to environmental stimuli.},
}
@article {pmid23315731,
year = {2013},
author = {Septer, AN and Lyell, NL and Stabb, EV},
title = {The iron-dependent regulator fur controls pheromone signaling systems and luminescence in the squid symbiont Vibrio fischeri ES114.},
journal = {Applied and environmental microbiology},
volume = {79},
number = {6},
pages = {1826-1834},
doi = {10.1128/AEM.03079-12},
pmid = {23315731},
issn = {1098-5336},
mesh = {Aliivibrio fischeri/genetics/metabolism/*physiology ; Animals ; Bacterial Proteins/*metabolism ; DNA, Bacterial/chemistry/genetics ; Decapodiformes/microbiology ; *Gene Expression Regulation, Bacterial ; Iron/metabolism ; Luminescence ; Molecular Sequence Data ; Pheromones/*metabolism ; Repressor Proteins/*metabolism ; Sequence Analysis, DNA ; *Signal Transduction ; Transcription Factors/metabolism ; },
abstract = {Bacteria often use pheromones to coordinate group behaviors in specific environments. While high cell density is required for pheromones to achieve stimulatory levels, environmental cues can also influence pheromone accumulation and signaling. For the squid symbiont Vibrio fischeri ES114, bioluminescence requires pheromone-mediated regulation, and this signaling is induced in the host to a greater extent than in culture, even at an equivalent cell density. Our goal is to better understand this environment-specific control over pheromone signaling and bioluminescence. Previous work with V. fischeri MJ1 showed that iron limitation induces luminescence, and we recently found that ES114 encounters a low-iron environment in its host. Here we show that ES114 induces luminescence at lower cell density and achieves brighter luminescence in low-iron media. This iron-dependent effect on luminescence required ferric uptake regulator (Fur), which we propose influences two pheromone signaling master regulators, LitR and LuxR. Genetic and bioinformatic analyses suggested that under low-iron conditions, Fur-mediated repression of litR is relieved, enabling more LitR to perform its established role as an activator of luxR. Interestingly, Fur may similarly control the LitR homolog SmcR of Vibrio vulnificus. These results reveal an intriguing regulatory link between low-iron conditions, which are often encountered in host tissues, and pheromone-dependent master regulators.},
}
@article {pmid23152924,
year = {2012},
author = {Septer, AN and Stabb, EV},
title = {Coordination of the arc regulatory system and pheromone-mediated positive feedback in controlling the Vibrio fischeri lux operon.},
journal = {PloS one},
volume = {7},
number = {11},
pages = {e49590},
doi = {10.1371/journal.pone.0049590},
pmid = {23152924},
issn = {1932-6203},
mesh = {Aliivibrio fischeri/cytology/*genetics ; Animal Structures/drug effects/microbiology ; Animals ; Bacterial Proteins/metabolism ; Decapodiformes/drug effects/microbiology ; Feedback, Physiological/*drug effects ; Gene Expression Regulation, Bacterial/*drug effects ; Genes, Bacterial/*genetics ; Luminescence ; Models, Biological ; Mutation/genetics ; Operon/*genetics ; Pheromones/*pharmacology ; },
abstract = {Bacterial pheromone signaling is often governed both by environmentally responsive regulators and by positive feedback. This regulatory combination has the potential to coordinate a group response among distinct subpopulations that perceive key environmental stimuli differently. We have explored the interplay between an environmentally responsive regulator and pheromone-mediated positive feedback in intercellular signaling by Vibrio fischeri ES114, a bioluminescent bacterium that colonizes the squid Euprymna scolopes. Bioluminescence in ES114 is controlled in part by N-(3-oxohexanoyl)-L-homoserine lactone (3OC6), a pheromone produced by LuxI that together with LuxR activates transcription of the luxICDABEG operon, initiating a positive feedback loop and inducing luminescence. The lux operon is also regulated by environmentally responsive regulators, including the redox-responsive ArcA/ArcB system, which directly represses lux in culture. Here we show that inactivating arcA leads to increased 3OC6 accumulation to initiate positive feedback. In the absence of positive feedback, arcA-mediated control of luminescence was only ∼2-fold, but luxI-dependent positive feedback contributed more than 100 fold to the net induction of luminescence in the arcA mutant. Consistent with this overriding importance of positive feedback, 3OC6 produced by the arcA mutant induced luminescence in nearby wild-type cells, overcoming their ArcA repression of lux. Similarly, we found that artificially inducing ArcA could effectively repress luminescence before, but not after, positive feedback was initiated. Finally, we show that 3OC6 produced by a subpopulation of symbiotic cells can induce luminescence in other cells co-colonizing the host. Our results suggest that even transient loss of ArcA-mediated regulation in a sub-population of cells can induce luminescence in a wider community. Moreover, they indicate that 3OC6 can communicate information about both cell density and the state of ArcA/ArcB.},
}
@article {pmid23144127,
year = {2013},
author = {Chavez-Dozal, A and Gorman, C and Erken, M and Steinberg, PD and McDougald, D and Nishiguchi, MK},
title = {Predation response of Vibrio fischeri biofilms to bacterivorus protists.},
journal = {Applied and environmental microbiology},
volume = {79},
number = {2},
pages = {553-558},
doi = {10.1128/AEM.02710-12},
pmid = {23144127},
issn = {1098-5336},
support = {R25 GM061222/GM/NIGMS NIH HHS/United States ; R25GM061222/GM/NIGMS NIH HHS/United States ; 1SC1AI081659-01/AI/NIAID NIH HHS/United States ; 3SC1AI081659-02S1/AI/NIAID NIH HHS/United States ; SC1 AI081659/AI/NIAID NIH HHS/United States ; },
mesh = {Adaptation, Biological ; Aliivibrio fischeri/*physiology ; Animals ; Biofilms/*growth & development ; Decapodiformes/microbiology/parasitology ; Kinetoplastida/*physiology ; *Microbial Interactions ; Seawater/microbiology/parasitology ; Tetrahymena pyriformis/*physiology ; },
abstract = {Vibrio fischeri proliferates in a sessile, stable community known as a biofilm, which is one alternative survival strategy of its life cycle. Although this survival strategy provides adequate protection from abiotic factors, marine biofilms are still susceptible to grazing by bacteria-consuming protozoa. Subsequently, grazing pressure can be controlled by certain defense mechanisms that confer higher biofilm antipredator fitness. In the present work, we hypothesized that V. fischeri exhibits an antipredator fitness behavior while forming biofilms. Different predators representing commonly found species in aquatic populations were examined, including the flagellates Rhynchomonas nasuta and Neobodo designis (early biofilm feeders) and the ciliate Tetrahymena pyriformis (late biofilm grazer). V. fischeri biofilms included isolates from both seawater and squid hosts (Euprymna and Sepiola species). Our results demonstrate inhibition of predation by biofilms, specifically, isolates from seawater. Additionally, antiprotozoan behavior was observed to be higher in late biofilms, particularly toward the ciliate T. pyriformis; however, inhibitory effects were found to be widespread among all isolates tested. These results provide an alternative explanation for the adaptive advantage and persistence of V. fischeri biofilms and provide an important contribution to the understanding of defensive mechanisms that exist in the out-of-host environment.},
}
@article {pmid23066064,
year = {2012},
author = {Ezenwa, VO and Gerardo, NM and Inouye, DW and Medina, M and Xavier, JB},
title = {Microbiology. Animal behavior and the microbiome.},
journal = {Science (New York, N.Y.)},
volume = {338},
number = {6104},
pages = {198-199},
doi = {10.1126/science.1227412},
pmid = {23066064},
issn = {1095-9203},
mesh = {Animals ; Anopheles/microbiology ; Anxiety/microbiology ; Bacteria/genetics ; Bacterial Adhesion/genetics ; Bacterial Secretion Systems/genetics ; *Behavior, Animal ; Decapodiformes/microbiology ; Drosophila melanogaster/microbiology ; Gastrointestinal Tract/microbiology ; Heteroptera/microbiology ; Host-Pathogen Interactions ; Humans ; Iguanas/microbiology ; Metagenome/*genetics/*physiology ; Mice ; Sexual Behavior, Animal ; Stress, Psychological/microbiology ; *Symbiosis ; },
}
@article {pmid23046951,
year = {2012},
author = {Dunn, AK},
title = {Vibrio fischeri metabolism: symbiosis and beyond.},
journal = {Advances in microbial physiology},
volume = {61},
number = {},
pages = {37-68},
doi = {10.1016/B978-0-12-394423-8.00002-0},
pmid = {23046951},
issn = {2162-5468},
mesh = {Aliivibrio fischeri/genetics/*physiology ; Animals ; Bacterial Proteins/genetics/metabolism ; Decapodiformes/*microbiology/physiology ; Fishes/*microbiology/physiology ; Metabolic Networks and Pathways ; Quorum Sensing ; *Symbiosis ; },
abstract = {Vibrio fischeri is a bioluminescent, Gram-negative marine bacterium that can be found free living and in a mutualistic association with certain squids and fishes. Over the past decades, the study of V. fischeri has led to important discoveries about bioluminescence, quorum sensing, and the mechanisms that underlie beneficial host-microbe interactions. This chapter highlights what has been learned about metabolic pathways in V. fischeri, and how this information contributes to a broader understanding of the role of bacterial metabolism in host colonization by both beneficial and pathogenic bacteria, as well as in the growth and survival of free-living bacteria.},
}
@article {pmid23042998,
year = {2012},
author = {Shibata, S and Yip, ES and Quirke, KP and Ondrey, JM and Visick, KL},
title = {Roles of the structural symbiosis polysaccharide (syp) genes in host colonization, biofilm formation, and polysaccharide biosynthesis in Vibrio fischeri.},
journal = {Journal of bacteriology},
volume = {194},
number = {24},
pages = {6736-6747},
doi = {10.1128/JB.00707-12},
pmid = {23042998},
issn = {1098-5530},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*genetics/*physiology ; Animals ; Bacterial Adhesion/*genetics ; Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Decapodiformes/*microbiology ; Gene Deletion ; Gene Expression Regulation, Bacterial ; *Genes, Bacterial ; Glass ; Polysaccharides, Bacterial/*biosynthesis ; Symbiosis/genetics ; },
abstract = {The symbiosis polysaccharide locus, syp, is required for Vibrio fischeri to form a symbiotic association with the squid Euprymna scolopes. It is also required for biofilm formation induced by the unlinked regulator RscS. The syp locus includes 18 genes that can be classified into four groups based on putative function: 4 genes encode putative regulators, 6 encode glycosyltransferases, 2 encode export proteins, and the remaining 6 encode proteins with other functions, including polysaccharide modification. To understand the roles of each of the 14 structural syp genes in colonization and biofilm formation, we generated nonpolar in-frame deletions of each gene. All of the deletion mutants exhibited defects in their ability to colonize juvenile squid, although the impact of the loss of SypB or SypI was modest. Consistent with their requirement for colonization, most of the structural genes were also required for RscS-induced biofilm formation. In particular, the production of wrinkled colonies, pellicles, and the matrix on the colony surface was eliminated or severely decreased in all mutants except for the sypB and sypI mutants; in contrast, only a subset of genes appeared to play a role in attachment to glass. Finally, immunoblotting data suggested that the structural Syp proteins are involved in polysaccharide production and/or export. These results provide important insights into the requirements for the syp genes under different environmental conditions and thus lay the groundwork for a more complete understanding of the matrix produced by V. fischeri to enhance cell-cell interactions and promote symbiotic colonization.},
}
@article {pmid22983036,
year = {2012},
author = {Rader, BA and Nyholm, SV},
title = {Host/microbe interactions revealed through "omics" in the symbiosis between the Hawaiian bobtail squid Euprymna scolopes and the bioluminescent bacterium Vibrio fischeri.},
journal = {The Biological bulletin},
volume = {223},
number = {1},
pages = {103-111},
doi = {10.1086/BBLv223n1p103},
pmid = {22983036},
issn = {1939-8697},
mesh = {Aliivibrio fischeri/growth & development/*physiology ; Animals ; Decapodiformes/immunology/*microbiology/*physiology ; Genomics/methods ; Immunity, Innate ; Proteomics/methods ; Quorum Sensing ; Reactive Nitrogen Species/toxicity ; Reactive Oxygen Species/toxicity ; Stress, Physiological ; *Symbiosis ; Transcriptome ; },
abstract = {The association between Euprymna scolopes, the Hawaiian bobtail squid, and Vibrio fischeri, a bioluminescent bacterium, has served as a model for beneficial symbioses for over 25 years. The experimental tractability of this association has helped researchers characterize many of the colonization events necessary for symbiosis. Recent technological advances, such as the sequenced genome of V. fischeri, DNA microarrays, and high-throughput transcriptomics and proteomics, have allowed for the identification of host and symbiont factors that are important in establishing and maintaining specificity in the association. We highlight some of these findings pertaining to quorum sensing, luminescence, responses to reactive oxygen and nitrogen species, recognition of microbe-associated molecular patterns by the innate immune system of the host, and a diel rhythm that helps regulate the symbiont population. We also discuss how comparative genomics has allowed the identification of symbiont factors important for specificity and why sequencing the host's genome should be a priority for the research community.},
}
@article {pmid22885637,
year = {2013},
author = {Guerrero-Ferreira, R and Gorman, C and Chavez, AA and Willie, S and Nishiguchi, MK},
title = {Characterization of the bacterial diversity in Indo-West Pacific loliginid and sepiolid squid light organs.},
journal = {Microbial ecology},
volume = {65},
number = {1},
pages = {214-226},
doi = {10.1007/s00248-012-0099-6},
pmid = {22885637},
issn = {1432-184X},
support = {R25 GM061222/GM/NIGMS NIH HHS/United States ; T34 GM007667/GM/NIGMS NIH HHS/United States ; 1SC1AI081659/AI/NIAID NIH HHS/United States ; SC1 AI081659-01/AI/NIAID NIH HHS/United States ; R25 GM048998/GM/NIGMS NIH HHS/United States ; S06 GM008136/GM/NIGMS NIH HHS/United States ; GM-61222-01/GM/NIGMS NIH HHS/United States ; SC1 AI081659-02/AI/NIAID NIH HHS/United States ; R25 GM48998/GM/NIGMS NIH HHS/United States ; T34GMO7667-34//PHS HHS/United States ; SC1 AI081659/AI/NIAID NIH HHS/United States ; SO6 GM008136-32 S2/GM/NIGMS NIH HHS/United States ; },
mesh = {Animal Structures/*microbiology ; Animals ; Australia ; Bacteriological Techniques ; DNA, Bacterial/genetics ; Decapodiformes/*microbiology ; Luminescence ; Metagenome ; Photobacterium/*classification/genetics/isolation & purification ; Phylogeny ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; *Symbiosis ; Thailand ; Vibrio/*classification/genetics/isolation & purification ; },
abstract = {Loliginid and sepiolid squid light organs are known to host a variety of bacterial species from the family Vibrionaceae, yet little is known about the species diversity and characteristics among different host squids. Here we present a broad-ranging molecular and physiological analysis of the bacteria colonizing light organs in loliginid and sepiolid squids from various field locations of the Indo-West Pacific (Australia and Thailand). Our PCR-RFLP analysis, physiological characterization, carbon utilization profiling, and electron microscopy data indicate that loliginid squid in the Indo-West Pacific carry a consortium of bacterial species from the families Vibrionaceae and Photobacteriaceae. This research also confirms our previous report of the presence of Vibrio harveyi as a member of the bacterial population colonizing light organs in loliginid squid. pyrH sequence data were used to confirm isolate identity, and indicates that Vibrio and Photobacterium comprise most of the light organ colonizers of squids from Australia, confirming previous reports for Australian loliginid and sepiolid squids. In addition, combined phylogenetic analysis of PCR-RFLP and 16S rDNA data from Australian and Thai isolates associated both Photobacterium and Vibrio clades with both loliginid and sepiolid strains, providing support that geographical origin does not correlate with their relatedness. These results indicate that both loliginid and sepiolid squids demonstrate symbiont specificity (Vibrionaceae), but their distribution is more likely due to environmental factors that are present during the infection process. This study adds significantly to the growing evidence for complex and dynamic associations in nature and highlights the importance of exploring symbiotic relationships in which non-virulent strains of pathogenic Vibrio species could establish associations with marine invertebrates.},
}
@article {pmid22710417,
year = {2012},
author = {Ray, VA and Morris, AR and Visick, KL},
title = {A semi-quantitative approach to assess biofilm formation using wrinkled colony development.},
journal = {Journal of visualized experiments : JoVE},
volume = {},
number = {64},
pages = {e4035},
doi = {10.3791/4035},
pmid = {22710417},
issn = {1940-087X},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; R01 GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Bacteriological Techniques/*methods ; Biofilms/*growth & development ; Colony Count, Microbial ; },
abstract = {Biofilms, or surface-attached communities of cells encapsulated in an extracellular matrix, represent a common lifestyle for many bacteria. Within a biofilm, bacterial cells often exhibit altered physiology, including enhanced resistance to antibiotics and other environmental stresses. Additionally, biofilms can play important roles in host-microbe interactions. Biofilms develop when bacteria transition from individual, planktonic cells to form complex, multi-cellular communities. In the laboratory, biofilms are studied by assessing the development of specific biofilm phenotypes. A common biofilm phenotype involves the formation of wrinkled or rugose bacterial colonies on solid agar media. Wrinkled colony formation provides a particularly simple and useful means to identify and characterize bacterial strains exhibiting altered biofilm phenotypes, and to investigate environmental conditions that impact biofilm formation. Wrinkled colony formation serves as an indicator of biofilm formation in a variety of bacteria, including both Gram-positive bacteria, such as Bacillus subtilis, and Gram-negative bacteria, such as Vibrio cholerae, Vibrio parahaemolyticus, Pseudomonas aeruginosa, and Vibrio fischeri. The marine bacterium V. fischeri has become a model for biofilm formation due to the critical role of biofilms during host colonization: biofilms produced by V. fischeri promote its colonization of the Hawaiian bobtail squid Euprymna scolopes. Importantly, biofilm phenotypes observed in vitro correlate with the ability of V. fischeri cells to effectively colonize host animals: strains impaired for biofilm formation in vitro possess a colonization defect, while strains exhibiting increased biofilm phenotypes are enhanced for colonization. V. fischeri therefore provides a simple model system to assess the mechanisms by which bacteria regulate biofilm formation and how biofilms impact host colonization. In this report, we describe a semi-quantitative method to assess biofilm formation using V. fischeri as a model system. This method involves the careful spotting of bacterial cultures at defined concentrations and volumes onto solid agar media; a spotted culture is synonymous to a single bacterial colony. This 'spotted culture' technique can be utilized to compare gross biofilm phenotypes at single, specified time-points (end-point assays), or to identify and characterize subtle biofilm phenotypes through time-course assays of biofilm development and measurements of the colony diameter, which is influenced by biofilm formation. Thus, this technique provides a semi-quantitative analysis of biofilm formation, permitting evaluation of the timing and patterning of wrinkled colony development and the relative size of the developing structure, characteristics that extend beyond the simple overall morphology.},
}
@article {pmid22636772,
year = {2012},
author = {Fidopiastis, PM and Rader, BA and Gerling, DG and Gutierrez, NA and Watkins, KH and Frey, MW and Nyholm, SV and Whistler, CA},
title = {Characterization of a Vibrio fischeri aminopeptidase and evidence for its influence on an early stage of squid colonization.},
journal = {Journal of bacteriology},
volume = {194},
number = {15},
pages = {3995-4002},
doi = {10.1128/JB.00108-12},
pmid = {22636772},
issn = {1098-5530},
mesh = {Aliivibrio fischeri/*enzymology/growth & development/*physiology ; Amino Acid Sequence ; Aminopeptidases/genetics/*metabolism ; Animal Structures/microbiology ; Animals ; Cloning, Molecular ; Decapodiformes/*microbiology ; Escherichia coli/genetics ; Gene Expression ; Kinetics ; Molecular Sequence Data ; Recombinant Proteins/genetics/isolation & purification/metabolism ; Sequence Homology, Amino Acid ; Substrate Specificity ; },
abstract = {Vibrio fischeri cells are the sole colonists of a specialized light organ in the mantle cavity of the sepiolid squid Euprymna scolopes. The process begins when the bacteria aggregate in mucus secretions outside the light organ. The cells eventually leave the aggregate, enter the light organ, and encounter a rich supply of peptides. The need to dissociate from mucus and presumably utilize peptides led us to hypothesize that protease activity is integral to the colonization process. Protease activity associated with whole cells of Vibrio fischeri strain ES114 was identified as the product of a putative cell membrane-associated aminopeptidase (PepN). To characterize this activity, the aminopeptidase was cloned, overexpressed, and purified. Initial steady-state kinetic studies revealed that the aminopeptidase has broad activity, with a preference for basic and hydrophobic side chains and k(cat) and K(m) values that are lower and smaller, respectively, than those of Escherichia coli PepN. A V. fischeri mutant unable to produce PepN is significantly delayed in its ability to colonize squid within the first 12 h, but eventually it establishes a wild-type colonization level. Likewise, in competition with the wild type for colonization, the mutant is outcompeted at 12 h postinoculation but then competes evenly by 24 h. Also, the PepN-deficient strain fails to achieve wild-type levels of cells in aggregates, suggesting an explanation for the initial colonization delay. This study provides a foundation for more studies on PepN expression, localization, and role in the early stages of squid colonization.},
}
@article {pmid22590467,
year = {2012},
author = {Collins, AJ and Schleicher, TR and Rader, BA and Nyholm, SV},
title = {Understanding the role of host hemocytes in a squid/vibrio symbiosis using transcriptomics and proteomics.},
journal = {Frontiers in immunology},
volume = {3},
number = {},
pages = {91},
doi = {10.3389/fimmu.2012.00091},
pmid = {22590467},
issn = {1664-3224},
abstract = {The symbiosis between the squid, Euprymna scolopes, and the bacterium, Vibrio fischeri, serves as a model for understanding interactions between beneficial bacteria and animal hosts. The establishment and maintenance of the association is highly specific and depends on the selection of V. fischeri and exclusion of non-symbiotic bacteria from the environment. Current evidence suggests that the host's cellular innate immune system, in the form of macrophage-like hemocytes, helps to mediate host tolerance of V. fischeri. To begin to understand the role of hemocytes in this association, we analyzed these cells by high-throughput 454 transcriptomic and liquid chromatography/tandem mass spectrometry (LC-MS/MS) proteomic analyses. 454 high-throughput sequencing produced 650, 686 reads totaling 279.9 Mb while LC-MS/MS analyses of circulating hemocytes putatively identified 702 unique proteins. Several receptors involved with the recognition of microbial-associated molecular patterns were identified. Among these was a complete open reading frame to a putative peptidoglycan recognition protein (EsPGRP5) with conserved residues for amidase activity. Assembly of the hemocyte transcriptome showed EsPGRP5 had high coverage, suggesting it is among the 5% most abundant transcripts in circulating hemocytes. Other transcripts and proteins identified included members of the conserved NF-κB signaling pathway, putative members of the complement pathway, the carbohydrate binding protein galectin, and cephalotoxin. Quantitative Real-Time PCR of complement-like genes, cephalotoxin, EsPGRP5, and a nitric oxide synthase showed differential expression in circulating hemocytes from adult squid with colonized light organs compared to those isolated from hosts where the symbionts were removed. These data suggest that the presence of the symbiont influences gene expression of the cellular innate immune system of E. scolopes.},
}
@article {pmid22550038,
year = {2012},
author = {Rader, BA and Kremer, N and Apicella, MA and Goldman, WE and McFall-Ngai, MJ},
title = {Modulation of symbiont lipid A signaling by host alkaline phosphatases in the squid-vibrio symbiosis.},
journal = {mBio},
volume = {3},
number = {3},
pages = {},
doi = {10.1128/mBio.00093-12},
pmid = {22550038},
issn = {2150-7511},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; AI 50661/AI/NIAID NIH HHS/United States ; RR 12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Alkaline Phosphatase/genetics/*metabolism ; Animals ; Decapodiformes/*enzymology/genetics/microbiology/*physiology ; Lipid A/*metabolism ; Molecular Sequence Data ; Phylogeny ; Signal Transduction ; *Symbiosis ; },
abstract = {UNLABELLED: The synergistic activity of Vibrio fischeri lipid A and the peptidoglycan monomer (tracheal cytotoxin [TCT]) induces apoptosis in the superficial cells of the juvenile Euprymna scolopes light organ during the onset of the squid-vibrio symbiosis. Once the association is established in the epithelium-lined crypts of the light organ, the host degrades the symbiont's constitutively produced TCT by the amidase activity of a peptidoglycan recognition protein (E. scolopes peptidoglycan recognition protein 2 [EsPGRP2]). In the present study, we explored the role of alkaline phosphatases in transforming the lipid A of the symbiont into a form that changes its signaling properties to host tissues. We obtained full-length open reading frames for two E. scolopes alkaline phosphatase (EsAP) mRNAs (esap1 and esap2); transcript levels suggested that the dominant light organ isoform is EsAP1. Levels of total EsAP activity increased with symbiosis, but only after the lipid A-dependent morphogenetic induction at 12 h, and were regulated over the day-night cycle. Inhibition of total EsAP activity impaired normal colonization and persistence by the symbiont. EsAP activity localized to the internal regions of the symbiotic juvenile light organ, including the lumina of the crypt spaces where the symbiont resides. These data provide evidence that EsAPs work in concert with EsPGRPs to change the signaling properties of bacterial products and thereby promote persistent colonization by the mutualistic symbiont.

IMPORTANCE: The potential for microbe-associated molecular patterns (MAMPs) to compromise host-tissue health is reflected in the often-used nomenclature for these molecules: lipopolysaccharide (LPS) is also called "endotoxin" and the peptidoglycan monomer is also called "tracheal cytotoxin" (TCT). With constant presentation of MAMPs by the normal microbiota, mechanisms to tolerate their effects have developed. The results of this contribution provide evidence that host alkaline phosphatases (APs) dephosphorylate and inactivate the symbiont MAMP lipid A. As such, APs work in synergy with a peptidoglycan recognition protein, which inactivates symbiont-exported TCT, to alter the symbiont MAMPs and promote persistence of the partnership. Not only may these activities serve to "tame" the MAMPs, but also the resulting products may themselves be important signals in persistent mutualisms. The finding of lipid A modification by APs in an invertebrate mutualism provides evidence that this specific strategy for dealing with symbiotic partners is conserved across the animal kingdom.},
}
@article {pmid22522684,
year = {2012},
author = {Mandel, MJ and Schaefer, AL and Brennan, CA and Heath-Heckman, EA and Deloney-Marino, CR and McFall-Ngai, MJ and Ruby, EG},
title = {Squid-derived chitin oligosaccharides are a chemotactic signal during colonization by Vibrio fischeri.},
journal = {Applied and environmental microbiology},
volume = {78},
number = {13},
pages = {4620-4626},
doi = {10.1128/AEM.00377-12},
pmid = {22522684},
issn = {1098-5336},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; AI55397/AI/NIAID NIH HHS/United States ; F32 GM078760/GM/NIGMS NIH HHS/United States ; RR012994/RR/NCRR NIH HHS/United States ; AI50661/AI/NIAID NIH HHS/United States ; T32 AI055397/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/growth & development/metabolism/*physiology ; Animals ; Chemotactic Factors/*metabolism ; *Chemotaxis ; Chitin/*metabolism ; Decapodiformes/metabolism/*microbiology ; Oligosaccharides/*metabolism ; Symbiosis ; },
abstract = {Chitin, a polymer of N-acetylglucosamine (GlcNAc), is noted as the second most abundant biopolymer in nature. Chitin serves many functions for marine bacteria in the family Vibrionaceae ("vibrios"), in some instances providing a physical attachment site, inducing natural genetic competence, and serving as an attractant for chemotaxis. The marine luminous bacterium Vibrio fischeri is the specific symbiont in the light-emitting organ of the Hawaiian bobtail squid, Euprymna scolopes. The bacterium provides the squid with luminescence that the animal uses in an antipredatory defense, while the squid supports the symbiont's nutritional requirements. V. fischeri cells are harvested from seawater during each host generation, and V. fischeri is the only species that can complete this process in nature. Furthermore, chitin is located in squid hemocytes and plays a nutritional role in the symbiosis. We demonstrate here that chitin oligosaccharides produced by the squid host serve as a chemotactic signal for colonizing bacteria. V. fischeri uses the gradient of host chitin to enter the squid light organ duct and colonize the animal. We provide evidence that chitin serves a novel function in an animal-bacterial mutualism, as an animal-produced bacterium-attracting synomone.},
}
@article {pmid22519773,
year = {2012},
author = {Soto, W and Punke, EB and Nishiguchi, MK},
title = {Evolutionary perspectives in a mutualism of sepiolid squid and bioluminescent bacteria: combined usage of microbial experimental evolution and temporal population genetics.},
journal = {Evolution; international journal of organic evolution},
volume = {66},
number = {5},
pages = {1308-1321},
doi = {10.1111/j.1558-5646.2011.01547.x},
pmid = {22519773},
issn = {1558-5646},
support = {R25 GM061222/GM/NIGMS NIH HHS/United States ; SC1 AI081659/AI/NIAID NIH HHS/United States ; 1SC1A1081659-01/SC/NCI NIH HHS/United States ; R25GM061222/GM/NIGMS NIH HHS/United States ; },
mesh = {Adhesins, Bacterial/genetics ; Aliivibrio fischeri/*genetics/physiology ; Animals ; *Biological Evolution ; Decapodiformes/*microbiology ; Environment ; *Genetic Variation ; Haplotypes ; Luminescent Measurements ; New South Wales ; Polymerase Chain Reaction ; Seasons ; Sequence Analysis, DNA ; Species Specificity ; *Symbiosis ; },
abstract = {The symbiosis between marine bioluminescent Vibrio bacteria and the sepiolid squid Euprymna is a model for studying animal-bacterial Interactions. Vibrio symbionts native to particular Euprymna species are competitively dominant, capable of outcompeting foreign Vibrio strains from other Euprymna host species. Despite competitive dominance, secondary colonization events by invading nonnative Vibrio fischeri have occurred. Competitive dominance can be offset through superior nonnative numbers and advantage of early start host colonization by nonnatives, granting nonnative vibrios an opportunity to establish beachheads in foreign Euprymna hosts. Here, we show that nonnative V. fischeri are capable of rapid adaptation to novel sepiolid squid hosts by serially passaging V. fischeri JRM200 (native to Hawaiian Euprymna scolopes) lines through the novel Australian squid host E. tasmanica for 500 generations. These experiments were complemented by a temporal population genetics survey of V. fischeri, collected from E. tasmanica over a decade, which provided a perspective from the natural history of V. fischeri evolution over 15,000-20,000 generations in E. tasmanica. No symbiont anagenic evolution within squids was observed, as competitive dominance does not purge V. fischeri genetic diversity through time. Instead, abiotic factors affecting abundance of V. fischeri variants in the planktonic phase sustain temporal symbiont diversity, a property itself of ecological constraints imposed by V. fischeri host adaptation.},
}
@article {pmid22504817,
year = {2012},
author = {Collins, AJ and LaBarre, BA and Won, BS and Shah, MV and Heng, S and Choudhury, MH and Haydar, SA and Santiago, J and Nyholm, SV},
title = {Diversity and partitioning of bacterial populations within the accessory nidamental gland of the squid Euprymna scolopes.},
journal = {Applied and environmental microbiology},
volume = {78},
number = {12},
pages = {4200-4208},
doi = {10.1128/AEM.07437-11},
pmid = {22504817},
issn = {1098-5336},
mesh = {Animals ; Bacteria/*classification/cytology/*isolation & purification ; *Biota ; Cluster Analysis ; DNA, Bacterial/chemistry/genetics ; DNA, Ribosomal/chemistry/genetics ; Decapodiformes/*microbiology ; Female ; Genitalia, Female/cytology/microbiology ; *Microbial Consortia ; Microscopy, Electron, Transmission ; Molecular Sequence Data ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; },
abstract = {Microbial consortia confer important benefits to animal and plant hosts, and model associations are necessary to examine these types of host/microbe interactions. The accessory nidamental gland (ANG) is a female reproductive organ found among cephalopod mollusks that contains a consortium of bacteria, the exact function of which is unknown. To begin to understand the role of this organ, the bacterial consortium was characterized in the Hawaiian bobtail squid, Euprymna scolopes, a well-studied model organism for symbiosis research. Transmission electron microscopy (TEM) analysis of the ANG revealed dense bacterial assemblages of rod- and coccus-shaped cells segregated by morphology into separate, epithelium-lined tubules. The host epithelium was morphologically heterogeneous, containing ciliated and nonciliated cells with various brush border thicknesses. Hemocytes of the host's innate immune system were also found in close proximity to the bacteria within the tubules. A census of 16S rRNA genes suggested that Rhodobacterales, Rhizobiales, and Verrucomicrobia bacteria were prevalent, with members of the genus Phaeobacter dominating the consortium. Analysis of 454-shotgun sequencing data confirmed the presence of members of these taxa and revealed members of a fourth, Flavobacteria of the Bacteroidetes phylum. 16S rRNA fluorescent in situ hybridization (FISH) revealed that many ANG tubules were dominated by members of specific taxa, namely, Rhodobacterales, Verrucomicrobia, or Cytophaga-Flavobacteria-Bacteroidetes, suggesting symbiont partitioning to specific host tubules. In addition, FISH revealed that bacteria, including Phaeobacter species from the ANG, are likely deposited into the jelly coat of freshly laid eggs. This report establishes the ANG of the invertebrate E. scolopes as a model to examine interactions between a bacterial consortium and its host.},
}
@article {pmid22500943,
year = {2012},
author = {Miyashiro, T and Ruby, EG},
title = {Shedding light on bioluminescence regulation in Vibrio fischeri.},
journal = {Molecular microbiology},
volume = {84},
number = {5},
pages = {795-806},
doi = {10.1111/j.1365-2958.2012.08065.x},
pmid = {22500943},
issn = {1365-2958},
support = {K99 GM097032/GM/NIGMS NIH HHS/United States ; K99 GM097032-01/GM/NIGMS NIH HHS/United States ; 1K99GM097032/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*genetics/*metabolism ; Animals ; Decapodiformes/microbiology/physiology ; *Gene Expression Regulation, Bacterial ; *Luminescence ; Luminescent Proteins/*metabolism ; Models, Theoretical ; Quorum Sensing ; Signal Transduction ; Symbiosis ; },
abstract = {The bioluminescence emitted by the marine bacterium Vibrio fischeri is a particularly striking result of individual microbial cells co-ordinating a group behaviour. The genes responsible for light production are principally regulated by the LuxR-LuxI quorum-sensing system. In addition to LuxR-LuxI, numerous other genetic elements and environmental conditions control bioluminescence production. Efforts to mathematically model the LuxR-LuxI system are providing insight into the dynamics of this autoinduction behaviour. The Hawaiian squid Euprymna scolopes forms a natural symbiosis with V. fischeri, and utilizes the symbiont-derived bioluminescence for certain nocturnal behaviours, such as counterillumination. Recent work suggests that the tissue with which V. fischeri associates not only can detect bioluminescence but may also use this light to monitor the V. fischeri population.},
}
@article {pmid22486781,
year = {2012},
author = {Chavez-Dozal, A and Hogan, D and Gorman, C and Quintanal-Villalonga, A and Nishiguchi, MK},
title = {Multiple Vibrio fischeri genes are involved in biofilm formation and host colonization.},
journal = {FEMS microbiology ecology},
volume = {81},
number = {3},
pages = {562-573},
doi = {10.1111/j.1574-6941.2012.01386.x},
pmid = {22486781},
issn = {1574-6941},
support = {R25 GM061222/GM/NIGMS NIH HHS/United States ; R25GM061222/GM/NIGMS NIH HHS/United States ; IOS-0744498//PHS HHS/United States ; 1SC1AI081659-01/AI/NIAID NIH HHS/United States ; SC1 AI081659/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*physiology ; Animals ; Bacterial Proteins/genetics/metabolism ; Biofilms ; Decapodiformes/*microbiology/physiology ; Fimbriae Proteins/genetics/metabolism ; Flagella/metabolism ; Genes, Regulator ; Mutation ; *Symbiosis ; Transcription Factors/metabolism ; },
abstract = {Biofilms are increasingly recognized as being the predominant form for survival for most bacteria in the environment. The successful colonization of Vibrio fischeri in its squid host Euprymna tasmanica involves complex microbe-host interactions mediated by specific genes that are essential for biofilm formation and colonization. Here, structural and regulatory genes were selected to study their role in biofilm formation and host colonization. We have mutated several genes (pilT, pilU, flgF, motY, ibpA and mifB) by an insertional inactivation strategy. The results demonstrate that structural genes responsible for synthesis of type IV pili and flagella are crucial for biofilm formation and host infection. Moreover, regulatory genes affect colony aggregation by various mechanisms, including alteration of synthesis of transcriptional factors and regulation of extracellular polysaccharide production. These results reflect the significance of how genetic alterations influence communal behavior, which is important in understanding symbiotic relationships.},
}
@article {pmid22414870,
year = {2012},
author = {Naughton, LM and Mandel, MJ},
title = {Colonization of Euprymna scolopes squid by Vibrio fischeri.},
journal = {Journal of visualized experiments : JoVE},
volume = {},
number = {61},
pages = {e3758},
doi = {10.3791/3758},
pmid = {22414870},
issn = {1940-087X},
mesh = {Aliivibrio fischeri/*growth & development/*isolation & purification ; Animals ; Bacteriological Techniques/*methods ; Colony Count, Microbial/methods ; Decapodiformes/*microbiology ; Luminescent Measurements/methods ; Seawater/microbiology ; Symbiosis ; },
abstract = {Specific bacteria are found in association with animal tissue. Such host-bacterial associations (symbioses) can be detrimental (pathogenic), have no fitness consequence (commensal), or be beneficial (mutualistic). While much attention has been given to pathogenic interactions, little is known about the processes that dictate the reproducible acquisition of beneficial/commensal bacteria from the environment. The light-organ mutualism between the marine Gram-negative bacterium V. fischeri and the Hawaiian bobtail squid, E. scolopes, represents a highly specific interaction in which one host (E. scolopes) establishes a symbiotic relationship with only one bacterial species (V. fischeri) throughout the course of its lifetime. Bioluminescence produced by V. fischeri during this interaction provides an anti-predatory benefit to E. scolopes during nocturnal activities, while the nutrient-rich host tissue provides V. fischeri with a protected niche. During each host generation, this relationship is recapitulated, thus representing a predictable process that can be assessed in detail at various stages of symbiotic development. In the laboratory, the juvenile squid hatch aposymbiotically (uncolonized), and, if collected within the first 30-60 minutes and transferred to symbiont-free water, cannot be colonized except by the experimental inoculum. This interaction thus provides a useful model system in which to assess the individual steps that lead to specific acquisition of a symbiotic microbe from the environment. Here we describe a method to assess the degree of colonization that occurs when newly hatched aposymbiotic E. scolopes are exposed to (artificial) seawater containing V. fischeri. This simple assay describes inoculation, natural infection, and recovery of the bacterial symbiont from the nascent light organ of E. scolopes. Care is taken to provide a consistent environment for the animals during symbiotic development, especially with regard to water quality and light cues. Methods to characterize the symbiotic population described include (1) measurement of bacterially-derived bioluminescence, and (2) direct colony counting of recovered symbionts.},
}
@article {pmid22374964,
year = {2012},
author = {Gyllborg, MC and Sahl, JW and Cronin, DC and Rasko, DA and Mandel, MJ},
title = {Draft genome sequence of Vibrio fischeri SR5, a strain isolated from the light organ of the Mediterranean squid Sepiola robusta.},
journal = {Journal of bacteriology},
volume = {194},
number = {6},
pages = {1639},
doi = {10.1128/JB.06825-11},
pmid = {22374964},
issn = {1098-5530},
mesh = {Aliivibrio fischeri/*genetics/isolation & purification ; Animal Structures/microbiology ; Animals ; DNA, Bacterial/*chemistry/*genetics ; Decapodiformes/*microbiology ; *Genome, Bacterial ; Mediterranean Sea ; Molecular Sequence Data ; Sequence Analysis, DNA ; },
abstract = {Here, we describe the draft genome sequence of Vibrio fischeri SR5, a squid symbiotic isolate from Sepiola robusta in the Mediterranean Sea. This 4.3-Mbp genome sequence represents the first V. fischeri genome from an S. robusta symbiont and the first from outside the Pacific Ocean.},
}
@article {pmid22247546,
year = {2012},
author = {Post, DM and Yu, L and Krasity, BC and Choudhury, B and Mandel, MJ and Brennan, CA and Ruby, EG and McFall-Ngai, MJ and Gibson, BW and Apicella, MA},
title = {O-antigen and core carbohydrate of Vibrio fischeri lipopolysaccharide: composition and analysis of their role in Euprymna scolopes light organ colonization.},
journal = {The Journal of biological chemistry},
volume = {287},
number = {11},
pages = {8515-8530},
doi = {10.1074/jbc.M111.324012},
pmid = {22247546},
issn = {1083-351X},
support = {P01 AI44642/AI/NIAID NIH HHS/United States ; R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM008692/GM/NIGMS NIH HHS/United States ; R01 AI50661/AI/NIAID NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01 RR 12294/RR/NCRR NIH HHS/United States ; R01 AI024616/AI/NIAID NIH HHS/United States ; T32 AI007414/AI/NIAID NIH HHS/United States ; R01 AI24616/AI/NIAID NIH HHS/United States ; P01 AI044642/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*metabolism/pathogenicity ; Animal Structures/microbiology ; Animals ; Bacterial Proteins/genetics/*metabolism ; Carbohydrate Conformation ; *Carbohydrate Metabolism ; Decapodiformes/*microbiology ; Ligases/genetics/*metabolism ; O Antigens/genetics/*metabolism ; },
abstract = {Vibrio fischeri exists in a symbiotic relationship with the Hawaiian bobtail squid, Euprymna scolopes, where the squid provides a home for the bacteria, and the bacteria in turn provide camouflage that helps protect the squid from night-time predators. Like other gram-negative organisms, V. fischeri expresses lipopolysaccharide (LPS) on its cell surface. The structure of the O-antigen and the core components of the LPS and their possible role in colonization of the squid have not previously been determined. In these studies, an O-antigen ligase mutant, waaL, was utilized to determine the structures of these LPS components and their roles in colonization of the squid. WaaL ligates the O-antigen to the core of the LPS; thus, LPS from waaL mutants lacks O-antigen. Our results show that the V. fischeri waaL mutant has a motility defect, is significantly delayed in colonization, and is unable to compete with the wild-type strain in co-colonization assays. Comparative analyses of the LPS from the wild-type and waaL strains showed that the V. fischeri LPS has a single O-antigen repeat composed of yersiniose, 8-epi-legionaminic acid, and N-acetylfucosamine. In addition, the LPS from the waaL strain showed that the core structure consists of L-glycero-D-manno-heptose, D-glycero-D-manno-heptose, glucose, 3-deoxy-D-manno-octulosonic acid, N-acetylgalactosamine, 8-epi-legionaminic acid, phosphate, and phosphoethanolamine. These studies indicate that the unusual V. fischeri O-antigen sugars play a role in the early phases of bacterial colonization of the squid.},
}
@article {pmid22233679,
year = {2012},
author = {Cao, X and Studer, SV and Wassarman, K and Zhang, Y and Ruby, EG and Miyashiro, T},
title = {The novel sigma factor-like regulator RpoQ controls luminescence, chitinase activity, and motility in Vibrio fischeri.},
journal = {mBio},
volume = {3},
number = {1},
pages = {},
doi = {10.1128/mBio.00285-11},
pmid = {22233679},
issn = {2150-7511},
support = {K99 GM097032/GM/NIGMS NIH HHS/United States ; 1K99GM097032/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; F32 GM084620/GM/NIGMS NIH HHS/United States ; 5F32GM084620/GM/NIGMS NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*genetics/isolation & purification/physiology ; Animals ; Chitinases/*metabolism ; Decapodiformes/microbiology/physiology ; Gene Deletion ; Gene Expression ; *Gene Expression Regulation, Bacterial ; *Locomotion ; Luminescence ; Luminescent Proteins/*metabolism ; Models, Biological ; Quorum Sensing ; Symbiosis ; Transcription Factors/genetics/*metabolism ; },
abstract = {UNLABELLED: Vibrio fischeri, the bacterial symbiont of the Hawaiian bobtail squid, Euprymna scolopes, uses quorum sensing to control genes involved in bioluminescence, host colonization, and other biological processes. Previous work has shown that AinS/R-directed quorum sensing also regulates the expression of rpoQ (VF_A1015), a gene annotated as an RpoS-like sigma factor. In this study, we demonstrate using phylogenetics that RpoQ is related to, but distinct from, the stationary-phase sigma factor RpoS. Overexpression of rpoQ results in elevated chitinase activity but decreased motility and luminescence, three activities associated with symbiosis. The reduction in bacterial luminescence associated with the overexpression of rpoQ occurs both in culture and within the light-emitting organ of the squid host. This suppression of bioluminescence is due to the repression of the luxICDABEG promoter. Our results highlight RpoQ as a novel regulatory component, embedded in the quorum-signaling network that controls several biological processes in V. fischeri.

IMPORTANCE: Quorum signaling is a widely occurring phenomenon that functions in diverse bacterial taxa. It is most often found associated with species that interact with animal or plant hosts, either as mutualists or pathogens, and controls the expression of genes critical to tissue colonization. We present the discovery of rpoQ, which encodes a new regulatory component in the quorum-signaling pathway of Vibrio fischeri. RpoQ is a novel protein in the RpoS family of stationary-phase sigma factors. Unlike many other regulatory proteins involved in the quorum-signaling pathways of the Vibrionaceae, the distribution of RpoQ appears to be restricted to only two closely related species. The role of this regulator is to enhance some quorum-signaling outputs (motility) while suppressing others (luminescence). We propose that RpoQ may be a recently evolved or acquired component in V. fischeri that provides this organism with an additional level of regulation to modulate its existing quorum-signaling pathway.},
}
@article {pmid22193955,
year = {2011},
author = {Serbus, LR and Ferreccio, A and Zhukova, M and McMorris, CL and Kiseleva, E and Sullivan, W},
title = {A feedback loop between Wolbachia and the Drosophila gurken mRNP complex influences Wolbachia titer.},
journal = {Journal of cell science},
volume = {124},
number = {Pt 24},
pages = {4299-4308},
doi = {10.1242/jcs.092510},
pmid = {22193955},
issn = {1477-9137},
support = {F32 GM080192/GM/NIGMS NIH HHS/United States ; R25 GM058903/GM/NIGMS NIH HHS/United States ; },
mesh = {Animals ; Drosophila Proteins/analysis/*genetics ; Drosophila melanogaster/genetics/microbiology/ultrastructure ; Feedback, Physiological ; Microtubules/physiology ; Oocytes/microbiology/ultrastructure ; Oogenesis ; RNA-Binding Proteins/analysis ; Ribonucleoproteins/*physiology ; Symbiosis ; Transforming Growth Factor alpha/*genetics ; Wolbachia/*physiology/ultrastructure ; },
abstract = {Although much is known about interactions between bacterial endosymbionts and their hosts, little is known concerning the host factors that influence endosymbiont titer. Wolbachia endosymbionts are globally dispersed throughout most insect species and are the causative agent in filarial nematode-mediated disease. Our investigation indicates that gurken (grk), a host gene encoding a crucial axis determinant, has a cumulative, dosage-sensitive impact on Wolbachia growth and proliferation during Drosophila oogenesis. This effect appears to be mediated by grk mRNA and its protein-binding partners Squid and Hrp48/Hrb27C, implicating the grk mRNA-protein (mRNP) complex as a rate-limiting host factor controlling Wolbachia titer. Furthermore, highly infected flies exhibit defects that match those occurring with disruption of grk mRNPs, such as nurse cell chromatin disruptions and malformation of chorionic appendages. These findings suggest a feedback loop in which Wolbachia interaction with the grk mRNP affects both Wolbachia titer and grk mRNP function.},
}
@article {pmid22182211,
year = {2012},
author = {Deloney-Marino, CR and Visick, KL},
title = {Role for cheR of Vibrio fischeri in the Vibrio-squid symbiosis.},
journal = {Canadian journal of microbiology},
volume = {58},
number = {1},
pages = {29-38},
doi = {10.1139/w11-107},
pmid = {22182211},
issn = {1480-3275},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; R01 GM059690-10/GM/NIGMS NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/enzymology/genetics/*physiology ; Amino Acid Sequence ; Animals ; Chemotaxis/genetics/*physiology ; Decapodiformes/*microbiology ; Gene Order ; Methyltransferases/genetics/*metabolism ; Molecular Sequence Data ; Mutation ; Sequence Alignment ; *Symbiosis ; },
abstract = {Upon hatching, the Hawaiian squid Euprymna scolopes is rapidly colonized by its symbiotic partner, the bioluminescent marine bacterium Vibrio fischeri . Vibrio fischeri cells present in the seawater enter the light organ of juvenile squid in a process that requires bacterial motility. In this study, we investigated the role chemotaxis may play in establishing this symbiotic colonization. Previously, we reported that V. fischeri migrates toward numerous attractants, including N-acetylneuraminic acid (NANA), a component of squid mucus. However, whether or not migration toward an attractant such as squid-derived NANA helps the bacterium to localize toward the light organ is unknown. When tested for the ability to colonize juvenile squid, a V. fischeri chemotaxis mutant defective for the methyltransferase CheR was outcompeted by the wild-type strain in co-inoculation experiments, even when the mutant was present in fourfold excess. Our results suggest that the ability to perform chemotaxis is an advantage during colonization, but not essential.},
}
@article {pmid22154556,
year = {2012},
author = {McFall-Ngai, M and Heath-Heckman, EA and Gillette, AA and Peyer, SM and Harvie, EA},
title = {The secret languages of coevolved symbioses: insights from the Euprymna scolopes-Vibrio fischeri symbiosis.},
journal = {Seminars in immunology},
volume = {24},
number = {1},
pages = {3-8},
doi = {10.1016/j.smim.2011.11.006},
pmid = {22154556},
issn = {1096-3618},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; R0-AI50661/AI/NIAID NIH HHS/United States ; R01 RR012294-16/RR/NCRR NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01-12294//PHS HHS/United States ; R01 AI050661-10/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*immunology ; Animals ; *Biological Evolution ; Decapodiformes/*immunology/*microbiology ; Immunity, Innate ; Receptors, Pattern Recognition/immunology ; *Symbiosis ; },
abstract = {Recent research on a wide variety of systems has demonstrated that animals generally coevolve with their microbial symbionts. Although such relationships are most often established anew each generation, the partners associate with fidelity, i.e., they form exclusive alliances within the context of rich communities of non-symbiotic environmental microbes. The mechanisms by which this exclusivity is achieved and maintained remain largely unknown. Studies of the model symbiosis between the Hawaiian squid Euprymna scolopes and the marine luminous bacterium Vibrio fischeri provide evidence that the interplay between evolutionarily conserved features of the innate immune system, most notably MAMP/PRR interactions, and a specific feature of this association, i.e., luminescence, are critical for development and maintenance of this association. As such, in this partnership and perhaps others, symbiotic exclusivity is mediated by the synergism between a general animal-microbe 'language' and a 'secret language' that is decipherable only by the specific partners involved.},
}
@article {pmid22114842,
year = {2011},
author = {Bowman, LA and McLean, S and Poole, RK and Fukuto, JM},
title = {The diversity of microbial responses to nitric oxide and agents of nitrosative stress close cousins but not identical twins.},
journal = {Advances in microbial physiology},
volume = {59},
number = {},
pages = {135-219},
doi = {10.1016/B978-0-12-387661-4.00006-9},
pmid = {22114842},
issn = {2162-5468},
mesh = {Bacteria/*drug effects/enzymology/genetics/*metabolism ; Bacterial Proteins/genetics/metabolism ; Nitric Oxide/metabolism/*pharmacology ; Nitric Oxide Synthase/genetics/metabolism ; Oxidative Stress/drug effects ; Reactive Nitrogen Species/metabolism/*pharmacology ; },
abstract = {Nitric oxide and related nitrogen species (reactive nitrogen species) now occupy a central position in contemporary medicine, physiology, biochemistry, and microbiology. In particular, NO plays important antimicrobial defenses in innate immunity but microbes have evolved intricate NO-sensing and defense mechanisms that are the subjects of a vast literature. Unfortunately, the burgeoning NO literature has not always been accompanied by an understanding of the intricacies and complexities of this radical and other reactive nitrogen species so that there exists confusion and vagueness about which one or more species exert the reported biological effects. The biological chemistry of NO and derived/related molecules is complex, due to multiple species that can be generated from NO in biological milieu and numerous possible reaction targets. Moreover, the fate and disposition of NO is always a function of its biological environment, which can vary significantly even within a single cell. In this review, we consider newer aspects of the literature but, most importantly, consider the underlying chemistry and draw attention to the distinctiveness of NO and its chemical cousins, nitrosonium (NO(+)), nitroxyl (NO(-), HNO), peroxynitrite (ONOO(-)), nitrite (NO(2)(-)), and nitrogen dioxide (NO(2)). All these species are reported to be generated in biological systems from initial formation of NO (from nitrite, NO synthases, or other sources) or its provision in biological experiments (typically from NO gas, S-nitrosothiols, or NO donor compounds). The major targets of NO and nitrosative damage (metal centers, thiols, and others) are reviewed and emphasis is given to newer "-omic" methods of unraveling the complex repercussions of NO and nitrogen oxide assaults. Microbial defense mechanisms, many of which are critical for pathogenicity, include the activities of hemoglobins that enzymically detoxify NO (to nitrate) and NO reductases and repair mechanisms (e.g., those that reverse S-nitrosothiol formation). Microbial resistance to these stresses is generally inducible and many diverse transcriptional regulators are involved-some that are secondary sensors (such as Fnr) and those that are "dedicated" (such as NorR, NsrR, NssR) in that their physiological function appears to be detecting primarily NO and then regulating expression of genes that encode enzymes with NO as a substrate. Although generally harmful, evidence is accumulating that NO may have beneficial effects, as in the case of the squid-Vibrio light-organ symbiosis, where NO serves as a signal, antioxidant, and specificity determinant. Progress in this area will require a thorough understanding not only of the biology but also of the underlying chemical principles.},
}
@article {pmid21998678,
year = {2011},
author = {Schleicher, TR and Nyholm, SV},
title = {Characterizing the host and symbiont proteomes in the association between the Bobtail squid, Euprymna scolopes, and the bacterium, Vibrio fischeri.},
journal = {PloS one},
volume = {6},
number = {10},
pages = {e25649},
doi = {10.1371/journal.pone.0025649},
pmid = {21998678},
issn = {1932-6203},
mesh = {Aliivibrio fischeri/*metabolism/physiology ; Animals ; Decapodiformes/cytology/immunology/*metabolism/*microbiology ; Electrophoresis, Gel, Two-Dimensional ; *Host-Pathogen Interactions ; Immunity, Innate ; Proteome/isolation & purification/*metabolism ; Proteomics/*methods ; Quorum Sensing ; Reactive Oxygen Species/metabolism ; Signal Transduction ; Stress, Physiological ; *Symbiosis ; },
abstract = {The beneficial symbiosis between the Hawaiian bobtail squid, Euprymna scolopes, and the bioluminescent bacterium, Vibrio fischeri, provides a unique opportunity to study host/microbe interactions within a natural microenvironment. Colonization of the squid light organ by V. fischeri begins a lifelong association with a regulated daily rhythm. Each morning the host expels an exudate from the light organ consisting of 95% of the symbiont population in addition to host hemocytes and shed epithelial cells. We analyzed the host and symbiont proteomes of adult squid exudate and surrounding light organ epithelial tissue using 1D- and 2D-polyacrylamide gel electrophoresis and multidimensional protein identification technology (MudPIT) in an effort to understand the contribution of both partners to the maintenance of this association. These proteomic analyses putatively identified 1581 unique proteins, 870 proteins originating from the symbiont and 711 from the host. Identified host proteins indicate a role of the innate immune system and reactive oxygen species (ROS) in regulating the symbiosis. Symbiont proteins detected enhance our understanding of the role of quorum sensing, two-component signaling, motility, and detoxification of ROS and reactive nitrogen species (RNS) inside the light organ. This study offers the first proteomic analysis of the symbiotic microenvironment of the adult light organ and provides the identification of proteins important to the regulation of this beneficial association.},
}
@article {pmid21992506,
year = {2011},
author = {Miyashiro, T and Klein, W and Oehlert, D and Cao, X and Schwartzman, J and Ruby, EG},
title = {The N-acetyl-D-glucosamine repressor NagC of Vibrio fischeri facilitates colonization of Euprymna scolopes.},
journal = {Molecular microbiology},
volume = {82},
number = {4},
pages = {894-903},
doi = {10.1111/j.1365-2958.2011.07858.x},
pmid = {21992506},
issn = {1365-2958},
support = {K99 GM097032/GM/NIGMS NIH HHS/United States ; K99 GM097032-01/GM/NIGMS NIH HHS/United States ; 1K99GM097032/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; F32 GM084620-03/GM/NIGMS NIH HHS/United States ; F32 GM084620/GM/NIGMS NIH HHS/United States ; 5F32GM084620/GM/NIGMS NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Acetylglucosamine/*biosynthesis ; Aliivibrio fischeri/genetics/growth & development/*physiology ; Animals ; Bacterial Load ; Decapodiformes/*microbiology ; *Gene Expression Regulation, Bacterial ; Repressor Proteins/genetics/*metabolism ; *Symbiosis ; Virulence Factors/genetics/*metabolism ; },
abstract = {To successfully colonize and persist within a host niche, bacteria must properly regulate their gene expression profiles. The marine bacterium Vibrio fischeri establishes a mutualistic symbiosis within the light organ of the Hawaiian squid, Euprymna scolopes. Here, we show that the repressor NagC of V. fischeri directly regulates several chitin- and N-acetyl-D-glucosamine-utilization genes that are co-regulated during productive symbiosis. We also demonstrate that repression by NagC is relieved in the presence of N-acetyl-D-glucosamine-6-phosphate, the intracellular form of N-acetyl-D-glucosamine. We find that gene repression by NagC is critical for efficient colonization of E. scolopes. Further, our study shows that NagC regulates genes that affect the normal dynamics of host colonization.},
}
@article {pmid21980988,
year = {2012},
author = {Wollenberg, MS and Preheim, SP and Polz, MF and Ruby, EG},
title = {Polyphyly of non-bioluminescent Vibrio fischeri sharing a lux-locus deletion.},
journal = {Environmental microbiology},
volume = {14},
number = {3},
pages = {655-668},
doi = {10.1111/j.1462-2920.2011.02608.x},
pmid = {21980988},
issn = {1462-2920},
support = {T32 GM007215/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01 GM099507/GM/NIGMS NIH HHS/United States ; 5T32GM007215-35/GM/NIGMS NIH HHS/United States ; R01 RR12294/RR/NCRR NIH HHS/United States ; T32 AI055397/AI/NIAID NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; 2T32AI055397-07/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*genetics/physiology ; Animals ; Bacterial Proteins/genetics/metabolism ; Base Sequence ; Decapodiformes/*genetics/microbiology/physiology ; Genes, Bacterial/physiology ; Light ; Locus Control Region ; Luminescent Measurements ; Luminescent Proteins/*genetics/metabolism ; Massachusetts ; Molecular Sequence Data ; Phylogeny ; Symbiosis/genetics ; },
abstract = {This study reports the first description and molecular characterization of naturally occurring, non-bioluminescent strains of Vibrio fischeri. These 'dark' V. fischeri strains remained non-bioluminescent even after treatment with both autoinducer and aldehyde, substrate additions that typically maximize light production in dim strains of luminous bacteria. Surprisingly, the entire lux locus (eight genes) was absent in over 97% of these dark V. fischeri strains. Although these strains were all collected from a Massachusetts (USA) estuary in 2007, phylogenetic reconstructions allowed us to reject the hypothesis that these newly described non-bioluminescent strains exhibit monophyly within the V. fischeri clade. These dark strains exhibited a competitive disadvantage against native bioluminescent strains when colonizing the light organ of the model V. fischeri host, the Hawaiian bobtail squid Euprymna scolopes. Significantly, we believe that the data collected in this study may suggest the first observation of a functional, parallel locus-deletion event among independent lineages of a non-pathogenic bacterial species.},
}
@article {pmid21883801,
year = {2011},
author = {Septer, AN and Wang, Y and Ruby, EG and Stabb, EV and Dunn, AK},
title = {The haem-uptake gene cluster in Vibrio fischeri is regulated by Fur and contributes to symbiotic colonization.},
journal = {Environmental microbiology},
volume = {13},
number = {11},
pages = {2855-2864},
doi = {10.1111/j.1462-2920.2011.02558.x},
pmid = {21883801},
issn = {1462-2920},
support = {R01 RR012294/RR/NCRR NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*genetics/physiology ; Animals ; Bacterial Proteins/genetics/metabolism ; Decapodiformes/*microbiology ; Gene Expression Regulation, Bacterial ; Genome, Bacterial ; Heme/*metabolism ; Hemin/metabolism ; Iron/metabolism ; *Multigene Family ; Promoter Regions, Genetic ; Repressor Proteins/genetics/metabolism ; Symbiosis/*genetics ; },
abstract = {Although it is accepted that bacteria-colonizing host tissues are commonly faced with iron-limiting conditions and that pathogenic bacteria often utilize iron from host-derived haem-based compounds, the mechanisms of iron acquisition by beneficial symbiotic bacteria are less clear. The bacterium Vibrio fischeri mutualistically colonizes the light organ of the squid Euprymna scolopes. Genome sequence analysis of V. fischeri revealed a putative haem-uptake gene cluster, and through mutant analysis we confirmed this cluster is important for haemin use by V. fischeri in culture. LacZ reporter assays demonstrated Fur-dependent transcriptional regulation of cluster promoter activity in culture. GFP-based reporter assays revealed that gene cluster promoter activity is induced in symbiotic V. fischeri as early as 14 h post inoculation, although colonization assays with the haem uptake mutant suggested an inability to uptake haem does not begin to limit colonization until later stages of the symbiosis. Our data indicate that the squid light organ is a low iron environment and that haem-based sources of iron are used by symbiotic V. fischeri cells. These findings provide important additional information on the availability of iron during symbiotic colonization of E. scolopes by V. fischeri, as well as the role of haem uptake in non-pathogenic host-microbe interactions.},
}
@article {pmid21854462,
year = {2011},
author = {Morris, AR and Darnell, CL and Visick, KL},
title = {Inactivation of a novel response regulator is necessary for biofilm formation and host colonization by Vibrio fischeri.},
journal = {Molecular microbiology},
volume = {82},
number = {1},
pages = {114-130},
doi = {10.1111/j.1365-2958.2011.07800.x},
pmid = {21854462},
issn = {1365-2958},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; R01 GM059690-10/GM/NIGMS NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/chemistry/genetics/*growth & development/*physiology ; Animals ; Bacterial Proteins/chemistry/*genetics/*metabolism ; *Biofilms ; Decapodiformes/*microbiology/physiology ; Gene Expression Regulation, Bacterial ; *Gene Silencing ; *Genes, Regulator ; Protein Structure, Tertiary ; Symbiosis ; },
abstract = {The marine bacterium Vibrio fischeri uses a biofilm to promote colonization of its eukaryotic host Euprymna scolopes. This biofilm depends on the symbiosis polysaccharide (syp) locus, which is transcriptionally regulated by the RscS-SypG two-component regulatory system. An additional response regulator (RR), SypE, exerts both positive and negative control over biofilm formation. SypE is a novel RR protein, with its three putative domains arranged in a unique configuration: a central phosphorylation receiver (REC) domain flanked by two effector domains with putative enzymatic activities (serine kinase and serine phosphatase). To determine how SypE regulates biofilm formation and host colonization, we generated a library of SypE domain mutants. Our results indicate that the N-terminus inhibits biofilm formation, while the C-terminus plays a positive role. The phosphorylation state of SypE appears to regulate these opposing activities, as disruption of the putative site of phosphorylation results in a protein that constitutively inhibits biofilm formation. Furthermore, SypE restricts host colonization: (i) sypE mutants with constitutive inhibitory activity fail to efficiently initiate host colonization and (ii) loss of sypE partially alleviates the colonization defect of an rscS mutant. We conclude that SypE must be inactivated to promote symbiotic colonization by V. fischeri.},
}
@article {pmid21819664,
year = {2011},
author = {Schärer, K and Savioz, S and Cernela, N and Saegesser, G and Stephan, R},
title = {Occurrence of Vibrio spp. in fish and shellfish collected from the Swiss market.},
journal = {Journal of food protection},
volume = {74},
number = {8},
pages = {1345-1347},
doi = {10.4315/0362-028X.JFP-11-001},
pmid = {21819664},
issn = {1944-9097},
mesh = {Animals ; Colony Count, Microbial ; *Consumer Product Safety ; Culture Media/chemistry ; DNA, Bacterial/analysis ; Food Contamination/*analysis ; Humans ; Polymerase Chain Reaction/methods ; Seafood/*microbiology ; Shellfish/*microbiology ; Species Specificity ; Switzerland ; Vibrio/classification/growth & development/*isolation & purification ; Virulence ; },
abstract = {The genus Vibrio includes gram-negative bacteria that inhabit estuarine ecosystems. V. cholerae, V. parahaemolyticus, and V. vulnificus pose a considerable public health threat as agents of sporadic and epidemic foodborne infections associated with the consumption of raw or undercooked contaminated fish or shellfish. In this study, we analyzed 138 fish and shellfish samples collected from the Swiss market (fish fillets [n = 102], bivalves [n = 34], and squid [n = 2]). Microbiological analysis was done according to International Organization for Standardization method 21872-1/21872-2:2007, using thiosulfate citrate bile sucrose agar and chromID Vibrio agar as selective agar. Presumptive-positive colonies on thiosulfate citrate bile sucrose agar or chromID Vibrio agar were picked and were identified by the API 20E and species-specific PCR systems. V. cholerae isolates were tested further by PCR for the presence of the cholera toxin A subunit gene (ctxA). V. parahaemolyticus isolates were tested by PCR for genes encoding for thermostable direct hemolysin (tdh) and TDH-related hemolysin (trh). V. cholerae was isolated from three samples and V. parahaemolyticus from eight samples. None of these strains harbored species-specific virulence factors. Further, V. alginolyticus was isolated from 40 samples, and V. fluvialis was isolated from 1 sample. Our study provides, for the first time, data for the assessment of exposure to Vibrio spp. in raw fish and bivalves consumed in Switzerland.},
}
@article {pmid21787344,
year = {2011},
author = {Krasity, BC and Troll, JV and Weiss, JP and McFall-Ngai, MJ},
title = {LBP/BPI proteins and their relatives: conservation over evolution and roles in mutualism.},
journal = {Biochemical Society transactions},
volume = {39},
number = {4},
pages = {1039-1044},
doi = {10.1042/BST0391039},
pmid = {21787344},
issn = {1470-8752},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; T32 GM008692/GM/NIGMS NIH HHS/United States ; R01 AI 50661/AI/NIAID NIH HHS/United States ; T32 AI007414/AI/NIAID NIH HHS/United States ; R01 AI059372/AI/NIAID NIH HHS/United States ; },
mesh = {Acute-Phase Proteins/*genetics/metabolism ; Amino Acid Sequence ; Animals ; Antimicrobial Cationic Peptides/*genetics/metabolism ; Blood Proteins/*genetics/metabolism ; Carrier Proteins/*genetics/metabolism ; *Conserved Sequence ; *Evolution, Molecular ; Humans ; Lipid Metabolism ; Membrane Glycoproteins/*genetics/metabolism ; Models, Biological ; Protein Binding ; Sequence Homology, Amino Acid ; Symbiosis/physiology ; },
abstract = {LBP [LPS (lipopolysaccharide)-binding protein] and BPI (bactericidal/permeability-increasing protein) are components of the immune system that have been principally studied in mammals for their involvement in defence against bacterial pathogens. These proteins share a basic architecture and residues involved in LPS binding. Putative orthologues, i.e. proteins encoded by similar genes that diverged from a common ancestor, have been found in a number of non-mammalian vertebrate species and several non-vertebrates. Similar to other aspects of immunity, such as the activity of Toll-like receptors and NOD (nucleotide-binding oligomerization domain) proteins, analysis of the conservation of LBPs and BPIs in the invertebrates promises to provide insight into features essential to the form and function of these molecules. This review considers state-of-the-art knowledge in the diversity of the LBP/BPI proteins across the eukaryotes and also considers their role in mutualistic symbioses. Recent studies of the LBPs and BPIs in an invertebrate model of beneficial associations, the Hawaiian bobtail squid Euprymna scolopes' alliance with the marine luminous bacterium Vibrio fischeri, are discussed as an example of the use of non-vertebrate models for the study of LBPs and BPIs.},
}
@article {pmid21776028,
year = {2012},
author = {Wollenberg, MS and Ruby, EG},
title = {Phylogeny and fitness of Vibrio fischeri from the light organs of Euprymna scolopes in two Oahu, Hawaii populations.},
journal = {The ISME journal},
volume = {6},
number = {2},
pages = {352-362},
doi = {10.1038/ismej.2011.92},
pmid = {21776028},
issn = {1751-7370},
support = {T32 GM007215/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; 5T32GM007215-35/GM/NIGMS NIH HHS/United States ; R01 RR12294/RR/NCRR NIH HHS/United States ; T32 AI055397/AI/NIAID NIH HHS/United States ; 2T32AI055397-07/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*classification/genetics/*physiology ; Animals ; Bays ; DNA Fingerprinting ; Decapodiformes/growth & development/*microbiology ; Genes, Bacterial/genetics ; Hawaii ; Molecular Sequence Data ; *Phylogeny ; Recombination, Genetic ; Symbiosis/physiology ; },
abstract = {The evolutionary relationship among Vibrio fischeri isolates obtained from the light organs of Euprymna scolopes collected around Oahu, Hawaii, were examined in this study. Phylogenetic reconstructions based on a concatenation of fragments of four housekeeping loci (recA, mdh, katA, pyrC) identified one monophyletic group ('Group-A') of V. fischeri from Oahu. Group-A V. fischeri strains could also be identified by a single DNA fingerprint type. V. fischeri strains with this fingerprint type had been observed to be at a significantly higher abundance than other strains in the light organs of adult squid collected from Maunalua Bay, Oahu, in 2005. We hypothesized that these previous observations might be related to a growth/survival advantage of the Group-A strains in the Maunalua Bay environments. Competition experiments between Group-A strains and non-Group-A strains demonstrated an advantage of the former in colonizing juvenile Maunalua Bay hosts. Growth and survival assays in Maunalua Bay seawater microcosms revealed a reduced fitness of Group-A strains relative to non-Group-A strains. From these results, we hypothesize that there may exist trade-offs between growth in the light organ and in seawater environments for local V. fischeri strains from Oahu. Alternatively, Group-A V. fischeri may represent an example of rapid, evolutionarily significant, specialization of a horizontally transmitted symbiont to a local host population.},
}
@article {pmid21723107,
year = {2011},
author = {Heath-Heckman, EA and McFall-Ngai, MJ},
title = {The occurrence of chitin in the hemocytes of invertebrates.},
journal = {Zoology (Jena, Germany)},
volume = {114},
number = {4},
pages = {191-198},
doi = {10.1016/j.zool.2011.02.002},
pmid = {21723107},
issn = {1873-2720},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; R01 RR012294-16/RR/NCRR NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01-12294//PHS HHS/United States ; R01 AI050661-10/AI/NIAID NIH HHS/United States ; R01-AI50661/AI/NIAID NIH HHS/United States ; },
mesh = {Animals ; Chitin/*biosynthesis ; Chitin Synthase/metabolism ; Decapodiformes/*chemistry ; Hemocytes/*chemistry ; RNA, Messenger/metabolism ; Symbiosis ; },
abstract = {The light-organ symbiosis of Euprymna scolopes, the Hawaiian bobtail squid, is a useful model for the study of animal-microbe interactions. Recent analyses have demonstrated that chitin breakdown products play a role in communication between E. scolopes and its bacterial symbiont Vibrio fischeri. In this study, we sought to determine the source of chitin in the symbiotic organ. We used a commercially available chitin-binding protein (CBP) conjugated to fluorescein to label the polymeric chitin in host tissues. Confocal microscopy revealed that the only cells in contact with the symbionts that labeled with the probe were the macrophage-like hemocytes, which traffic into the light-organ crypts where the bacteria reside. Labeling of extracted hemocytes by CBP was markedly decreased following treatment with purified chitinase, providing further evidence that the labeled molecule is polymeric chitin. Further, CBP-positive areas co-localized with both a halide peroxidase antibody and Lysotracker, a lysosomal marker, suggesting that the chitin-like biomolecule occurs in the lysosome or acidic vacuoles. Reverse transcriptase polymerase chain reaction (PCR) of hemocytes revealed mRNA coding for a chitin synthase, suggesting that the hemocytes synthesize chitin de novo. Finally, upon surveying blood cells from other invertebrate species, we observed CBP-positive regions in all granular blood cells examined, suggesting that this feature is a shared character among the invertebrates; the vertebrate blood cells that we sampled did not label with CBP. Although the function of the chitin-like material remains undetermined, its presence and subcellular location in invertebrate hemocytes suggests a conserved role for this polysaccharide in the immune system of diverse animals.},
}
@article {pmid21656812,
year = {2011},
author = {Chavez-Dozal, A and Nishiguchi, MK},
title = {Variation in biofilm formation among symbiotic and free-living strains of Vibrio fischeri.},
journal = {Journal of basic microbiology},
volume = {51},
number = {5},
pages = {452-458},
doi = {10.1002/jobm.201000426},
pmid = {21656812},
issn = {1521-4028},
support = {R25 GM061222/GM/NIGMS NIH HHS/United States ; R25GM061222/GM/NIGMS NIH HHS/United States ; SC1AI081659/AI/NIAID NIH HHS/United States ; R25 GM061222-10/GM/NIGMS NIH HHS/United States ; SC1 AI081659/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/isolation & purification/*physiology ; Biodiversity ; Biofilms/*growth & development ; Salinity ; *Symbiosis ; Temperature ; },
abstract = {Persistence and survival under various environmental stresses has been attributed to the capacity of most bacteria to form biofilms. In aquatic environments, the symbiotic bacterium Vibrio fischeri survives variable abiotic conditions during its free-living stage that dictates its ability to colonize the squid host. In the present study, the influence of different abiotic factors such as salt concentration, temperature, static/dynamic conditions, and carbon source availability were tested to determine whether biofilm formation occurred in 26 symbiotic and free-living V. fischeri strains. Statistical analysis indicate that most strains examined were strong biofilm producers under salinity concentrations that ranged between 1-5%, mesophilic temperatures (25-30 °C) and static conditions. Moreover, free-living strains are generally better biofilm formers than the symbiotically competent ones. Geographical location (strain origin) also correlated with biofilm formation. These findings provide evidence that abiotic growth conditions are important for determining whether mutualistic V. fischeri have the capacity to produce complex biofilms, allowing for increased competency and specificity during symbiosis.},
}
@article {pmid21498521,
year = {2011},
author = {Phillips, NJ and Adin, DM and Stabb, EV and McFall-Ngai, MJ and Apicella, MA and Gibson, BW},
title = {The lipid A from Vibrio fischeri lipopolysaccharide: a unique structure bearing a phosphoglycerol moiety.},
journal = {The Journal of biological chemistry},
volume = {286},
number = {24},
pages = {21203-21219},
doi = {10.1074/jbc.M111.239475},
pmid = {21498521},
issn = {1083-351X},
support = {P30 CA082103/CA/NCI NIH HHS/United States ; R01 AI024616/AI/NIAID NIH HHS/United States ; R01 AI050661/AI/NIAID NIH HHS/United States ; AI-50661/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*metabolism ; Animals ; Decapodiformes/*microbiology ; Fatty Acids/chemistry ; Gas Chromatography-Mass Spectrometry/methods ; Glycerophosphates/chemistry ; Lipid A/*chemistry ; Lipopolysaccharides/*metabolism ; Models, Chemical ; Phosphatidic Acids/chemistry ; Phosphorylation ; Spectrometry, Mass, Electrospray Ionization/methods ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Symbiosis ; Tandem Mass Spectrometry/methods ; },
abstract = {Vibrio fischeri, a bioluminescent marine bacterium, exists in an exclusive symbiotic relationship with the Hawaiian bobtail squid, Euprymna scolopes, whose light organ it colonizes. Previously, it has been shown that the lipopolysaccharide (LPS) or free lipid A of V. fischeri can trigger morphological changes in the juvenile squid's light organ that occur upon colonization. To investigate the structural features that might be responsible for this phenomenon, the lipid A from V. fischeri ES114 LPS was isolated and characterized by multistage mass spectrometry (MS(n)). A microheterogeneous mixture of mono- and diphosphorylated diglucosamine disaccharides was observed with variable states of acylation ranging from tetra- to octaacylated forms. All lipid A species, however, contained a set of conserved primary acyl chains consisting of an N-linked C14:0(3-OH) at the 2-position, an unusual N-linked C14:1(3-OH) at the 2'-position, and two O-linked C12:0(3-OH) fatty acids at the 3- and 3'-positions. The fatty acids found in secondary acylation were considerably more variable, with either a C12:0 or C16:1 at the 2-position, C14:0 or C14:0(3-OH) at the 2'-position, and C12:0 or no substituent at the 3'-position. Most surprising was the presence of an unusual set of modifications at the secondary acylation site of the 3-position consisting of phosphoglycerol (GroP), lysophosphatidic acid (GroP bearing C12:0, C16:0, or C16:1), or phosphatidic acid (GroP bearing either C16:0 + C12:0 or C16:0 + C16:1). Given their unusual nature, it is possible that these features of the V. fischeri lipid A may underlie the ability of E. scolopes to recognize its symbiotic partner.},
}
@article {pmid21425442,
year = {2011},
author = {Rosenberg, E and Zilber-Rosenberg, I},
title = {Symbiosis and development: the hologenome concept.},
journal = {Birth defects research. Part C, Embryo today : reviews},
volume = {93},
number = {1},
pages = {56-66},
doi = {10.1002/bdrc.20196},
pmid = {21425442},
issn = {1542-9768},
mesh = {Adaptation, Biological ; Animals ; Anthozoa/genetics/*microbiology ; Biological Evolution ; Developmental Biology ; Epigenomics ; Genetic Variation ; Humans ; Insecta/genetics/*microbiology ; *Metagenome ; Mice ; Nitrogen Fixation ; Plants/genetics/*microbiology ; *Symbiosis ; },
abstract = {All animals and plants establish symbiotic relationships with microorganisms; often the combined genetic information of the diverse microbiota exceeds that of the host. How the genetic wealth of the microbiota affects all aspects of the holobiont's (host plus all of its associated microorganisms) fitness (adaptation, survival, development, growth and reproduction) and evolution is reviewed, using selected coral, insect, squid, plant, and human/mouse published experimental results. The data are discussed within the framework of the hologenome theory of evolution, which demonstrates that changes in environmental parameters, for example, diet, can cause rapid changes in the diverse microbiota, which not only can benefit the holobiont in the short term but also can be transmitted to offspring and lead to long lasting cooperations. As acquired characteristics (microbes) are heritable, consideration of the holobiont as a unit of selection in evolution leads to neo-Lamarckian principles within a Darwinian framework. The potential application of these principles can be seen in the growing fields of prebiotics and probiotics.},
}
@article {pmid21338463,
year = {2011},
author = {Wang, Y and Ruby, EG},
title = {The roles of NO in microbial symbioses.},
journal = {Cellular microbiology},
volume = {13},
number = {4},
pages = {518-526},
doi = {10.1111/j.1462-5822.2011.01576.x},
pmid = {21338463},
issn = {1462-5822},
support = {R01 GM099507/GM/NIGMS NIH HHS/United States ; R01 OD011024/OD/NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01 RR 12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Antioxidants/metabolism ; Bacteria/*metabolism ; Decapodiformes/anatomy & histology/microbiology ; Host-Pathogen Interactions ; Nitric Oxide/*metabolism ; Plants/metabolism/microbiology ; Signal Transduction/physiology ; *Symbiosis ; Vibrio/metabolism ; },
abstract = {Because of its unique chemical properties, nitric oxide (NO) is a pluripotent signalling and effector molecule that is implicated in a variety of biological roles. Although NO is known to function in host innate immunity against pathogen invasion, its possible roles in microbial symbioses with animal and plant hosts remain relatively less well defined. In this review, we discuss the mechanisms by which bacteria sense and/or detoxify NO. We then focus specifically on its roles in microbial symbioses of diverse eukaryotic hosts. Using the squid-vibrio light-organ symbiosis as a well-characterized example, we discuss the ways in which NO serves as a signal, antioxidant and specificity determinant in this model symbiosis. Because beneficial microbial associations are older and much more prevalent than pathogenic ones, it seems likely that the former may be evolutionary precursors of the latter. Thus, knowledge of the roles played by NO in mutualisms will provide insights into its function in disease interactions as well.},
}
@article {pmid21091598,
year = {2011},
author = {Altura, MA and Stabb, E and Goldman, W and Apicella, M and McFall-Ngai, MJ},
title = {Attenuation of host NO production by MAMPs potentiates development of the host in the squid-vibrio symbiosis.},
journal = {Cellular microbiology},
volume = {13},
number = {4},
pages = {527-537},
doi = {10.1111/j.1462-5822.2010.01552.x},
pmid = {21091598},
issn = {1462-5822},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; RR R01-12294/RR/NCRR NIH HHS/United States ; AI55397/AI/NIAID NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; T32 AI055397/AI/NIAID NIH HHS/United States ; R01-AI50661/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Animals ; Decapodiformes/anatomy & histology/metabolism/*microbiology ; *Host-Pathogen Interactions ; Light ; Morphogenesis ; Nitric Oxide/*metabolism ; Nitric Oxide Donors/metabolism ; Nitric Oxide Synthase/metabolism ; Symbiosis/*physiology ; },
abstract = {Bacterial pathogens typically upregulate the host's production of nitric oxide synthase (NOS) and nitric oxide (NO) as antimicrobial agents, a response that is often mediated by microbe-associated molecular patterns (MAMPs) of the pathogen. In contrast, previous studies of the beneficial Euprymna scolopes/Vibrio fischeri symbiosis demonstrated that symbiont colonization results in attenuation of host NOS/NO, which occurs in high levels in hatchling light organs. Here, we sought to determine whether V. fischeri MAMPs, specifically lipopolysaccharide (LPS) and the peptidoglycan derivative tracheal cytotoxin (TCT), attenuate NOS/NO, and whether this activity mediates the MAMPs-induced light organ morphogenesis. Using confocal microscopy, we characterized levels of NOS with immunocytochemistry and NO with a NO-specific fluorochrome. When added exogenously to seawater containing hatchling animals, V. fischeri LPS and TCT together, but not individually, induced normal NOS/NO attenuation. Further, V. fischeri mutants defective in TCT release did not. Experiments with NOS inhibitors and NO donors provided evidence that NO mediates apoptosis and morphogenesis associated with symbiont colonization. Attenuation of NOS/NO by LPS and TCT in the squid-vibrio symbiosis provides another example of how the host's response to MAMPs depends on the context. These data also provide a mechanism by which symbiont MAMPs regulate host development.},
}
@article {pmid21091210,
year = {2011},
author = {Archetti, M and Ubeda, F and Fudenberg, D and Green, J and Pierce, NE and Yu, DW},
title = {Let the right one in: a microeconomic approach to partner choice in mutualisms.},
journal = {The American naturalist},
volume = {177},
number = {1},
pages = {75-85},
doi = {10.1086/657622},
pmid = {21091210},
issn = {1537-5323},
mesh = {Aliivibrio fischeri/physiology ; Animals ; Ants/physiology ; *Biological Evolution ; Decapodiformes/microbiology/physiology ; Economics ; *Models, Biological ; Plant Physiological Phenomena ; *Symbiosis ; },
abstract = {One of the main problems impeding the evolution of cooperation is partner choice. When information is asymmetric (the quality of a potential partner is known only to himself), it may seem that partner choice is not possible without signaling. Many mutualisms, however, exist without signaling, and the mechanisms by which hosts might select the right partners are unclear. Here we propose a general mechanism of partner choice, "screening," that is similar to the economic theory of mechanism design. Imposing the appropriate costs and rewards may induce the informed individuals to screen themselves according to their types and therefore allow a noninformed individual to establish associations with the correct partners in the absence of signaling. Several types of biological symbioses are good candidates for screening, including bobtail squid, ant-plants, gut microbiomes, and many animal and plant species that produce reactive oxygen species. We describe a series of diagnostic tests for screening. Screening games can apply to the cases where by-products, partner fidelity feedback, or host sanctions do not apply, therefore explaining the evolution of mutualism in systems where it is impossible for potential symbionts to signal their cooperativeness beforehand and where the host does not punish symbiont misbehavior.},
}
@article {pmid21075896,
year = {2011},
author = {Zamborsky, DJ and Nishiguchi, MK},
title = {Phylogeographical patterns among Mediterranean sepiolid squids and their Vibrio symbionts: environment drives specificity among sympatric species.},
journal = {Applied and environmental microbiology},
volume = {77},
number = {2},
pages = {642-649},
doi = {10.1128/AEM.02105-10},
pmid = {21075896},
issn = {1098-5336},
support = {SC1 AI081659/AI/NIAID NIH HHS/United States ; 1SC1AI081659/AI/NIAID NIH HHS/United States ; SC1AI81659-02S1/AI/NIAID NIH HHS/United States ; },
mesh = {Animals ; Cluster Analysis ; Decapodiformes/*microbiology ; *Genetic Variation ; Geography ; Host Specificity ; Mediterranean Sea ; Phylogeny ; Sequence Analysis, DNA ; *Symbiosis ; Vibrio/*classification/genetics/isolation & purification/*physiology ; },
abstract = {Bobtail squid from the genera Sepiola and Rondeletiola (Cephalopoda: Sepiolidae) form mutualistic associations with luminous Gram-negative bacteria (Gammaproteobacteria: Vibrionaceae) from the genera Vibrio and Photobacterium. Symbiotic bacteria proliferate inside a bilobed light organ until they are actively expelled by the host into the surrounding environment on a diel basis. This event results in a dynamic symbiont population with the potential to establish the symbiosis with newly hatched sterile (axenic) juvenile sepiolids. In this study, we examined the genetic diversity found in populations of sympatric sepiolid squid species and their symbionts by the use of nested clade analysis with multiple gene analyses. Variation found in the distribution of different species of symbiotic bacteria suggests a strong influence of abiotic factors in the local environment, affecting bacterial distribution among sympatric populations of hosts. These abiotic factors include temperature differences incurred by a shallow thermocline, as well as a lack of strong coastal water movement accompanied by seasonal temperature changes in overlapping niches. Host populations are stable and do not appear to have a significant role in the formation of symbiont populations relative to their distribution across the Mediterranean Sea. Additionally, all squid species examined (Sepiola affinis, S. robusta, S. ligulata, S. intermedia, and Rondeletiola minor) are genetically distinct from one another regardless of location and demonstrate very little intraspecific variation within species. These findings suggest that physical boundaries and distance in relation to population size, and not host specificity, are important factors in limiting or defining gene flow within sympatric marine squids and their associated bacterial symbionts in the Mediterranean Sea.},
}
@article {pmid21035464,
year = {2011},
author = {Archetti, M},
title = {Contract theory for the evolution of cooperation: The right incentives attract the right partners.},
journal = {Journal of theoretical biology},
volume = {269},
number = {1},
pages = {201-207},
doi = {10.1016/j.jtbi.2010.10.025},
pmid = {21035464},
issn = {1095-8541},
mesh = {Aliivibrio fischeri/physiology ; Animals ; *Biological Evolution ; Decapodiformes/microbiology ; *Models, Biological ; *Motivation ; Reward ; Symbiosis/*physiology ; },
abstract = {Partner choice is a critical stage of many biological interactions, from mating to cooperation. When the quality of the potential partners is unknown, one way to choose is to rely on signaling: costly signals can reveal the quality of the sender and allow the receiver to choose. In some cases, however, signaling (or an active choice based on signals) is not possible, for example in the initiation of the symbiosis between the squid Euprymna scolopes and the bioluminescent bacterium Vibrio fischeri. How is partner choice possible in this and other similar cases? I show that in a game with asymmetric information without signaling, imposing a deliberate cost for establishing the interaction allows the non-informed individual to attract the right partner if the cost induces only high quality individuals to accept the interaction. Furthermore, imposing different costs and rewards may induce the informed individuals to screen themselves according to their types, and therefore allow the non-informed individual to establish an association with the correct partners in the absence of signaling.},
}
@article {pmid20942825,
year = {2010},
author = {Leigh, EG},
title = {The evolution of mutualism.},
journal = {Journal of evolutionary biology},
volume = {23},
number = {12},
pages = {2507-2528},
doi = {10.1111/j.1420-9101.2010.02114.x},
pmid = {20942825},
issn = {1420-9101},
mesh = {Animals ; *Biological Evolution ; Competitive Behavior ; *Cooperative Behavior ; Ecosystem ; Models, Biological ; Symbiosis ; Trees/physiology ; },
abstract = {Like altruism, mutualism, cooperation between species, evolves only by enhancing all participants' inclusive fitness. Mutualism evolves most readily between members of different kingdoms, which pool complementary abilities for mutual benefit: some of these mutualisms represent major evolutionary innovations. Mutualism cannot persist if cheating annihilates its benefits. In long-term mutualisms, symbioses, at least one party associates with the other nearly all its life. Usually, a larger host harbours smaller symbionts. Cheating is restrained by vertical transmission, as in Buchnera; partner fidelity, as among bull-thorn acacias and protective ants; test-based choice of symbionts, as bobtail squid choose bioluminescent bacteria; or sanctioning nonperforming symbionts, as legumes punish nonperforming nitrogen-fixing bacteria. Mutualisms involving brief exchanges, as among plants and seed-dispersers, however, persist despite abundant cheating. Both symbioses and brief-exchange mutualisms have transformed whole ecosystems. These mutualisms may be steps towards ecosystems which, like Adam Smith's ideal economy, serve their members' common good.},
}
@article {pmid20815823,
year = {2010},
author = {Wang, Y and Dunn, AK and Wilneff, J and McFall-Ngai, MJ and Spiro, S and Ruby, EG},
title = {Vibrio fischeri flavohaemoglobin protects against nitric oxide during initiation of the squid-Vibrio symbiosis.},
journal = {Molecular microbiology},
volume = {78},
number = {4},
pages = {903-915},
doi = {10.1111/j.1365-2958.2010.07376.x},
pmid = {20815823},
issn = {1365-2958},
support = {R01 RR012294/RR/NCRR NIH HHS/United States ; R01 RR 12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aerobiosis ; Aliivibrio fischeri/*immunology/*physiology ; Anaerobiosis ; Animals ; Bacterial Proteins/*metabolism ; Decapodiformes/*immunology/*microbiology ; Gene Expression Profiling ; Hemeproteins/*metabolism ; Nitric Oxide/*metabolism/toxicity ; Repressor Proteins/metabolism ; *Symbiosis ; },
abstract = {Nitric oxide (NO) is implicated in a wide range of biological processes, including innate immunity against pathogens, signal transduction and protection against oxidative stress. However, its possible roles in beneficial host-microbe associations are less well recognized. During the early stages of the squid-vibrio symbiosis, the bacterial symbiont Vibrio fischeri encounters host-derived NO, which has been hypothesized to serve as a specificity determinant. We demonstrate here that the flavohaemoglobin, Hmp, of V. fischeri protects against NO, both in culture and during colonization of the squid host. Transcriptional analyses indicate that hmp expression is highly responsive to NO, principally through the repressor, NsrR. Hmp protects V. fischeri from NO inhibition of aerobic respiration, and removes NO under both oxic and anoxic conditions. A Δhmp mutant of V. fischeri initiates squid colonization less effectively than wild type, but is rescued by the presence of an NO synthase inhibitor. The hmp promoter is activated during the initial stage of colonization, during which the Δhmp strain fails to form normal-sized aggregates of colonizing cells. Taken together, these results suggest that the sensing of host-derived NO by NsrR, and the subsequent removal of NO by Hmp, influence aggregate size and, thereby, V. fischeri colonization efficiency.},
}
@article {pmid20693328,
year = {2010},
author = {Lyell, NL and Dunn, AK and Bose, JL and Stabb, EV},
title = {Bright mutants of Vibrio fischeri ES114 reveal conditions and regulators that control bioluminescence and expression of the lux operon.},
journal = {Journal of bacteriology},
volume = {192},
number = {19},
pages = {5103-5114},
doi = {10.1128/JB.00524-10},
pmid = {20693328},
issn = {1098-5530},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*metabolism ; Bacterial Proteins/genetics/*metabolism ; DNA Transposable Elements/genetics/physiology ; Genetic Complementation Test ; Guanine/metabolism ; *Luminescence ; Magnesium/metabolism ; Models, Biological ; Mutation/genetics ; Operon/genetics/*physiology ; Phosphates/metabolism ; },
abstract = {Vibrio fischeri ES114, an isolate from the Euprymna scolopes light organ, produces little bioluminescence in culture but is ∼1,000-fold brighter when colonizing the host. Cell-density-dependent regulation alone cannot explain this phenomenon, because cells within colonies on solid medium are much dimmer than symbiotic cells despite their similar cell densities. To better understand this low luminescence in culture, we screened ∼20,000 mini-Tn5 mutants of ES114 for increased luminescence and identified 28 independent "luminescence-up" mutants with insertions in 14 loci. Mutations affecting the Pst phosphate uptake system led to the discovery that luminescence is upregulated under low-phosphate conditions by PhoB, and we also found that ainS, which encodes an autoinducer synthase, mediates repression of luminescence during growth on plates. Other novel luminescence-up mutants had insertions in acnB, topA, tfoY, phoQ, guaB, and two specific tRNA genes. Two loci, hns and lonA, were previously described as repressors of bioluminescence in transgenic Escherichia coli carrying the light-generating lux genes, and mutations in arcA and arcB were consistent with our report that Arc represses lux. Our results reveal a complex regulatory web governing luminescence and show how certain environmental conditions are integrated into regulation of the pheromone-dependent lux system.},
}
@article {pmid20680094,
year = {2010},
author = {Guerrero-Ferreira, RC and Nishiguchi, MK},
title = {Differential gene expression in bacterial symbionts from loliginid squids demonstrates variation between mutualistic and environmental niches.},
journal = {Environmental microbiology reports},
volume = {2},
number = {4},
pages = {514-523},
doi = {10.1111/j.1758-2229.2009.00077.x},
pmid = {20680094},
issn = {1758-2229},
support = {SC1 AI081659/AI/NIAID NIH HHS/United States ; SC1 AI081659-01/AI/NIAID NIH HHS/United States ; SC1 AI081659-02/AI/NIAID NIH HHS/United States ; },
abstract = {Luminescent bacteria (gamma-Proteobacteria: Vibrionaceae) are found in complex bilobed light organs of both sepiolid and loliginid squids (Mollusca: Cephalopoda). Despite the existence of multiple strain colonization between Vibrio bacteria and loliginid squids, specificity at the genus level still exists and may influence interactions between symbiotic and free-living stages of the symbiont. The environmentally transmitted behaviour of Vibrio symbionts bestows a certain degree of recognition that exists prior and subsequent to the colonization process. Therefore, we identified bacterial genes required for successful colonization of loliginid light organs by examining transcripts solely expressed in either the light organ or free-living stages. Selective capture of transcribed sequences (SCOTS) was used to differentiate genes expressed by the same bacterium when thriving in two different environments (i.e. loliginid light organs and seawater). Genes specific for squid light organs included vulnibactin synthetase, outer membrane protein W and dihydroxy dehydratase, which have been associated with the maintenance of bacterial host associations in other systems. In contrast, genes that were solely expressed in the free-living condition consisted of transcripts recognized as important factors for bacterial survival in the environment. These transcripts included genes for methyl accepting chemotaxis proteins, arginine decarboxylase and chitinase. These results provide valuable information regarding mechanisms determining specificity, establishment, and maintenance of bacteria-squid associations.},
}
@article {pmid21966913,
year = {2010},
author = {Troll, JV and Bent, EH and Pacquette, N and Wier, AM and Goldman, WE and Silverman, N and McFall-Ngai, MJ},
title = {Taming the symbiont for coexistence: a host PGRP neutralizes a bacterial symbiont toxin.},
journal = {Environmental microbiology},
volume = {12},
number = {8},
pages = {2190-2203},
doi = {10.1111/j.1462-2920.2009.02121.x},
pmid = {21966913},
issn = {1462-2920},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; RR R01-12294/RR/NCRR NIH HHS/United States ; AI55397/AI/NIAID NIH HHS/United States ; R01 AI060025/AI/NIAID NIH HHS/United States ; T32 AI055397/AI/NIAID NIH HHS/United States ; R01 AI050661-08/AI/NIAID NIH HHS/United States ; R01-AI50661/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*growth & development ; Amidohydrolases/metabolism ; Animals ; Bacterial Toxins/*antagonists & inhibitors ; Carrier Proteins/*metabolism/secretion ; Cytotoxins/antagonists & inhibitors ; Decapodiformes/*metabolism/*microbiology ; Epithelium/metabolism/secretion ; Morphogenesis ; Mucus/chemistry ; *Symbiosis ; },
abstract = {In horizontally transmitted mutualisms between marine animals and their bacterial partners, the host environment promotes the initial colonization by specific symbionts that it harvests from the surrounding bacterioplankton. Subsequently, the host must develop long-term tolerance to immunogenic bacterial molecules, such as peptidoglycan and lipopolysaccaride derivatives. We describe the characterization of the activity of a host peptidoglycan recognition protein (EsPGRP2) during establishment of the symbiosis between the squid Euprymna scolopes and its luminous bacterial symbiont Vibrio fischeri. Using confocal immunocytochemistry, we localized EsPGRP2 to all epithelial surfaces of the animal, and determined that it is exported in association with mucus shedding. Most notably, EsPGRP2 was released by the crypt epithelia into the extracellular spaces housing the symbionts. This translocation occurred only after the symbionts had triggered host morphogenesis, a process that is induced by exposure to the peptidoglycan monomer tracheal cytotoxin (TCT), a bacterial 'toxin' that is constitutively exported by V. fischeri. Enzymatic analyses demonstrated that, like many described PGRPs, EsPGRP2 has a TCT-degrading amidase activity. The timing of EsPGRP2 export into the crypts provides evidence that the host does not export this protein until after TCT induces morphogenesis, and thereafter EsPGRP2 is constantly present in the crypts ameliorating the effects of V. fischeri TCT.},
}
@article {pmid21966901,
year = {2010},
author = {Morris, AR and Visick, KL},
title = {Control of biofilm formation and colonization in Vibrio fischeri: a role for partner switching?.},
journal = {Environmental microbiology},
volume = {12},
number = {8},
pages = {2051-2059},
doi = {10.1111/j.1462-2920.2010.02269.x},
pmid = {21966901},
issn = {1462-2920},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; R01 GM059690-10/GM/NIGMS NIH HHS/United States ; R01 GM059690-11/GM/NIGMS NIH HHS/United States ; R01GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*growth & development/metabolism ; Amino Acid Sequence ; Animals ; Bacterial Proteins/genetics/*metabolism ; *Biofilms ; Decapodiformes/*microbiology ; Genes, Bacterial ; Genes, Regulator ; Molecular Sequence Data ; *Symbiosis ; },
abstract = {Bacteria employ a variety of mechanisms to promote and control colonization of their respective hosts, including restricting the expression of genes necessary for colonization to distinct situations (i.e. encounter with a prospective host). In the symbiosis between the marine bacterium Vibrio fischeri and its host squid, Euprymna scolopes, colonization proceeds via a transient biofilm formed by the bacterium. The production of this bacterial biofilm depends on a complex regulatory network that controls transcription of the symbiosis polysaccharide (syp) gene locus. In addition to this transcriptional control, biofilm formation is regulated by two proteins, SypA and SypE, which may function in an unusual regulatory mechanism known as partner switching. Best characterized in Bacillus subtilis and other Gram-positive bacteria, partner switching is a signalling mechanism that provides dynamic regulatory control over bacterial gene expression. The involvement of putative partner-switching components within V. fischeri suggests that tight regulatory control over biofilm formation may be important for the lifestyle of this organism.},
}
@article {pmid20662783,
year = {2010},
author = {Miyashiro, T and Wollenberg, MS and Cao, X and Oehlert, D and Ruby, EG},
title = {A single qrr gene is necessary and sufficient for LuxO-mediated regulation in Vibrio fischeri.},
journal = {Molecular microbiology},
volume = {77},
number = {6},
pages = {1556-1567},
doi = {10.1111/j.1365-2958.2010.07309.x},
pmid = {20662783},
issn = {1365-2958},
support = {R01 RR012294-15/RR/NCRR NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; F32 GM084620-03/GM/NIGMS NIH HHS/United States ; F32 GM084620/GM/NIGMS NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*genetics/metabolism ; Animals ; Bacterial Proteins/genetics/*metabolism ; Computational Biology ; Conserved Sequence ; Decapodiformes/microbiology ; Gene Expression Regulation, Bacterial ; Genes, Bacterial ; Luminescence ; Phylogeny ; Repressor Proteins/genetics/*metabolism ; Sequence Analysis, DNA ; },
abstract = {All members of the Vibrionaceae harbour LuxO, a response regulator that integrates outputs from various signalling systems, ultimately controlling specific traits that are crucial to the distinct biology of each species. LuxO is phosphorylated in response to low cell density, activating the transcription of a family of small RNAs called Qrrs, which in turn, control the levels of a global regulatory protein conserved within the Vibrionaceae. Although the function of each Qrr is similar, the number of qrr genes varies among the different species. Using a bioinformatics approach, we have determined the number of qrr genes in fully sequenced Vibrionaceae members. Phylogenetic analysis suggests the most recent common ancestor of all Vibrionaceae shared a single, ancestral qrr gene, which duplicated and diverged into multiple qrr genes in some present-day vibrio lineages. To demonstrate that a single qrr gene is sufficient to mediate repression of LitR, the global regulator in Vibrio fischeri, we have performed a series of genetic and phenotypic analyses of the LuxO pathway and its output. Our studies contribute to a better understanding of the ancestral state of these pathways in vibrios, as well as to the evolution and divergence of other sRNAs within different bacterial lineages.},
}
@article {pmid20544735,
year = {2010},
author = {Fraune, S and Bosch, TC},
title = {Why bacteria matter in animal development and evolution.},
journal = {BioEssays : news and reviews in molecular, cellular and developmental biology},
volume = {32},
number = {7},
pages = {571-580},
doi = {10.1002/bies.200900192},
pmid = {20544735},
issn = {1521-1878},
mesh = {Animals ; Bacteria/*metabolism ; *Biological Evolution ; Epithelium/microbiology ; *Growth and Development ; Humans ; Intestines/growth & development/immunology/microbiology ; Symbiosis ; },
abstract = {While largely studied because of their harmful effects on human health, there is growing appreciation that bacteria are important partners for invertebrates and vertebrates, including man. Epithelia in metazoans do not only select their microbiota; a coevolved consortium of microbes enables both invertebrates and vertebrates to expand the range of diet supply, to shape the complex immune system and to control pathogenic bacteria. Microbes in zebrafish and mice regulate gut epithelial homeostasis. In a squid, microbes control the development of the symbiotic light organ. These discoveries point to a key role for bacteria in any metazoan existence, and imply that beneficial bacteria-host interactions should be considered an integral part of development and evolution.},
}
@article {pmid20487269,
year = {2010},
author = {Spiro, S},
title = {An alternative route to nitric oxide resistance.},
journal = {Molecular microbiology},
volume = {77},
number = {1},
pages = {6-10},
doi = {10.1111/j.1365-2958.2010.07195.x},
pmid = {20487269},
issn = {1365-2958},
mesh = {Aliivibrio fischeri/drug effects/immunology/*physiology ; Animals ; Anti-Bacterial Agents/*toxicity ; Bacterial Proteins/metabolism ; Decapodiformes/immunology/microbiology/*physiology ; *Drug Resistance, Bacterial ; Mitochondrial Proteins ; Nitric Oxide/*toxicity ; Oxidoreductases/*metabolism ; Oxygen Consumption ; Plant Proteins ; *Symbiosis ; },
abstract = {Vibrio fischeri is a bioluminescent bacterium that enters into a symbiosis with the bobtail squid Euprymna scolopes. The bacterium colonizes a specialized light organ, in which it generates light that might help the squid to hide its silhouette from animals beneath it. Previous studies have shown that the host nitric oxide (NO) synthase is active during colonization, suggesting that V. fischeri symbionts are exposed to NO. Thus, NO might play a role in regulating the symbiosis, a role possibly analogous to that of NO in the interaction between some pathogens and their hosts. One possibility is that NO helps to exclude other species from the light organ, in which case, the response of V. fischeri to NO is of considerable interest. In this issue of Molecular Microbiology, Dunn et al. report that V. fischeri produces an NO-inducible and NO-resistant alternative oxidase (Aox) that allows respiration to continue in the presence of NO concentrations that are inhibitory to the conventional respiratory oxidases. This is an important step towards a better understanding of the role that NO plays in the Vibrio-squid symbiosis, and provides the first indication of a physiological function for a bacterial homologue of the plant Aox.},
}
@article {pmid20404170,
year = {2010},
author = {Wang, Y and Dufour, YS and Carlson, HK and Donohue, TJ and Marletta, MA and Ruby, EG},
title = {H-NOX-mediated nitric oxide sensing modulates symbiotic colonization by Vibrio fischeri.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {107},
number = {18},
pages = {8375-8380},
doi = {10.1073/pnas.1003571107},
pmid = {20404170},
issn = {1091-6490},
support = {R01 GM075273-04/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; GM070671/GM/NIGMS NIH HHS/United States ; R01 GM075273/GM/NIGMS NIH HHS/United States ; R01 GM070671/GM/NIGMS NIH HHS/United States ; GM075273/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*growth & development/*metabolism ; Bacterial Proteins/genetics/*metabolism ; Gene Deletion ; Gene Expression Profiling ; Heme/metabolism ; Hemin/metabolism ; Iron/metabolism ; Ligands ; Mutation ; Nitric Oxide/*metabolism ; },
abstract = {The bioluminescent bacterium Vibrio fischeri initiates a specific, persistent symbiosis in the light organ of the squid Euprymna scolopes. During the early stages of colonization, V. fischeri is exposed to host-derived nitric oxide (NO). Although NO can be both an antimicrobial component of innate immunity and a key signaling molecule in eukaryotes, potential roles in beneficial host-microbe associations have not been described. V. fischeri hnoX encodes a heme NO/oxygen-binding (H-NOX) protein, a member of a family of bacterial NO- and/or O(2)-binding proteins of unknown function. We hypothesized that H-NOX acts as a NO sensor that is involved in regulating symbiosis-related genes early in colonization. Whole-genome expression studies identified 20 genes that were repressed in an NO- and H-NOX-dependent fashion. Ten of these, including hemin-utilization genes, have a promoter with a putative ferric-uptake regulator (Fur) binding site. As predicted, in the presence of NO, wild-type V. fischeri grew more slowly on hemin than a hnoX deletion mutant. Host-colonization studies showed that the hnoX mutant was also 10-fold more efficient in initially colonizing the squid host than the wild type; similarly, in mixed inoculations, it outcompeted the wild-type strain by an average of 16-fold after 24 h. However, the presence of excess hemin or iron reversed this dominance. The advantage of the mutant in colonizing the iron-limited light-organ tissues is caused, at least in part, by its greater ability to acquire host-derived hemin. Our data suggest that V. fischeri normally senses a host-generated NO signal through H-NOX(Vf) and modulates the expression of its iron uptake capacity during the early stages of the light-organ symbiosis.},
}
@article {pmid20394824,
year = {2010},
author = {Zhang, J and Li, F and Jiang, H and Yu, Y and Liu, C and Li, S and Wang, B and Xiang, J},
title = {Proteomic analysis of differentially expressed proteins in lymphoid organ of Fenneropenaeus chinensis response to Vibrio anguillarum stimulation.},
journal = {Fish & shellfish immunology},
volume = {29},
number = {2},
pages = {186-194},
doi = {10.1016/j.fsi.2010.03.011},
pmid = {20394824},
issn = {1095-9947},
mesh = {Animals ; Electrophoresis, Gel, Two-Dimensional ; Gene Expression Profiling ; Gene Expression Regulation/*immunology ; Lymphoid Tissue/*immunology ; Penaeidae/*immunology/*microbiology ; *Proteomics ; Vibrio/*immunology ; },
abstract = {To gain an insight into the function of shrimp lymphoid organ at protein level, we analyzed the proteome of lymphoid organ in healthy Chinese shrimp Fenneropenaeus chinensis (F. chinensis) through two-dimensional gel electrophoresis (2-DE) based proteomic approach. A total of 95 spots representing 75 protein entries were identified by liquid chromatography tandem mass spectrometry (LC-MS/MS) with both online and in-house database. According to Gene Ontology (GO) annotation of biological process, the identified proteins were classified into 13 categories. Among them, approximately 36% of proteins related to cytoskeleton are noticeable. Then, a comparative proteomic approach was employed to investigate the differentially expressed proteins in lymphoid organ of Vibrio anguillarum-challenged F. chinensis. At 24 h post-injection (hpi), 17 differentially expressed protein spots were successfully identified, including 4 up-regulated protein spots (represent 4 proteins: cathepsin L, protein similar to squid CG16901-PC, protein kinase C and protein similar to T-complex Chaperonin 5 CG8439-PA), and 13 down-regulated protein spots (represent 9 proteins: actin, beta-actin, cytoplasmic actin CyII, alpha tubulin, beta tubulin, protein similar to proteasome delta, vacuolar ATP synthase subunit B, elongation factor 2, carboxypeptidase B). These data may help us to understand the function of lymphoid organ and the molecular immune mechanism of shrimp responsive to pathogen infection.},
}
@article {pmid20298504,
year = {2010},
author = {Septer, AN and Bose, JL and Dunn, AK and Stabb, EV},
title = {FNR-mediated regulation of bioluminescence and anaerobic respiration in the light-organ symbiont Vibrio fischeri.},
journal = {FEMS microbiology letters},
volume = {306},
number = {1},
pages = {72-81},
doi = {10.1111/j.1574-6968.2010.01938.x},
pmid = {20298504},
issn = {1574-6968},
support = {F32 GM020041-02/GM/NIGMS NIH HHS/United States ; R01 A150661//PHS HHS/United States ; },
mesh = {Aliivibrio fischeri/*metabolism ; Anaerobiosis ; Animals ; Bacterial Proteins/genetics/*metabolism ; Cloning, Molecular ; Decapodiformes/microbiology ; Escherichia coli/genetics/metabolism ; Fumarates/metabolism ; Gene Knockout Techniques ; *Luminescence ; Nitrates/metabolism ; Oxidation-Reduction ; *Symbiosis ; Transcription Factors/genetics/*metabolism ; },
abstract = {Vibrio fischeri induces both anaerobic respiration and bioluminescence during symbiotic infection. In many bacteria, the oxygen-sensitive regulator FNR activates anaerobic respiration, and a preliminary study using the light-generating lux genes from V. fischeri MJ1 cloned in Escherichia coli suggested that FNR stimulates bioluminescence. To test for FNR-mediated regulation of bioluminescence and anaerobic respiration in V. fischeri, we generated fnr mutants of V. fischeri strains MJ1 and ES114. In both strains, FNR was required for normal fumarate- and nitrate-dependent respiration. However, contrary to the report in transgenic E. coli, FNR mediated the repression of lux. ArcA represses bioluminescence, and P(arcA)-lacZ reporters showed reduced expression in fnr mutants, suggesting a possible indirect effect of FNR on bioluminescence via arcA. Finally, the fnr mutant of ES114 was not impaired in colonization of its host squid, Euprymna scolopes. This study extends the characterization of FNR to the Vibrionaceae and underscores the importance of studying lux regulation in its native background.},
}
@article {pmid20150890,
year = {2010},
author = {Collins, AJ and Nyholm, SV},
title = {Obtaining hemocytes from the Hawaiian bobtail squid Euprymna scolopes and observing their adherence to symbiotic and non-symbiotic bacteria.},
journal = {Journal of visualized experiments : JoVE},
volume = {},
number = {36},
pages = {},
doi = {10.3791/1714},
pmid = {20150890},
issn = {1940-087X},
mesh = {Animals ; Cell Adhesion/physiology ; Cell Separation/*methods ; Decapodiformes/*cytology/microbiology ; Hemocytes/*cytology/physiology ; Symbiosis ; Vibrio/*physiology ; },
abstract = {Studies concerning the role of the immune system in mediating molecular signaling between beneficial bacteria and their hosts have, in recent years, made significant contributions to our understanding of the co-evolution of eukaryotes with their microbiota. The symbiotic association between the Hawaiian bobtail squid, Euprymna scolopes and the bioluminescent bacterium Vibrio fischeri has been utilized as a model system for understanding the effects of beneficial bacteria on animal development. Recent studies have shown that macrophage-like hemocytes, the sole cellular component of the squid host's innate immune system, likely play an important role in mediating the establishment and maintenance of this association. This protocol will demonstrate how to obtain hemocytes from E. scolopes and then use these cells in bacterial binding assays. Adult squid are first anesthetized before hemolymph is collected by syringe from the main cephalic blood vessel. The host hemocytes, contained in the extracted hemolymph, are adhered to chambered glass coverslips and then exposed to green fluorescent protein-labeled symbiotic Vibrio fischeri and non-symbiotic Vibrio harveyi. The hemocytes are counterstained with a fluorescent dye (Cell Tracker Orange, Invitrogen) and then visualized using fluorescent microscopy.},
}
@article {pmid20150047,
year = {2009},
author = {Lee, PN and McFall-Ngai, MJ and Callaerts, P and de Couet, HG},
title = {The Hawaiian bobtail squid (Euprymna scolopes): a model to study the molecular basis of eukaryote-prokaryote mutualism and the development and evolution of morphological novelties in cephalopods.},
journal = {Cold Spring Harbor protocols},
volume = {2009},
number = {11},
pages = {pdb.emo135},
doi = {10.1101/pdb.emo135},
pmid = {20150047},
issn = {1559-6095},
mesh = {Animal Husbandry ; Animal Structures/*embryology ; Animals ; *Biological Evolution ; Decapodiformes/*anatomy & histology/genetics ; Eukaryotic Cells/*physiology ; Genomics ; Hawaii ; *Models, Animal ; Prokaryotic Cells/*physiology ; Symbiosis/*physiology ; },
abstract = {The Hawaiian bobtail squid, Euprymna scolopes, is a cephalopod whose small size, short lifespan, rapid growth, and year-round availability make it suitable as a model organism. E. scolopes is studied in three principal contexts: (1) as a model of cephalopod development; (2) as a model of animal-bacterial symbioses; and (3) as a system for studying adaptations of tissues that interact with light. E. scolopes embryos can be obtained continually and can be reared in the laboratory over an entire generation. The embryos and protective chorions are optically clear, facilitating in situ developmental observations, and can be manipulated experimentally. Many molecular protocols have been developed for studying E. scolopes development. This species is best known, however, for its symbiosis with the luminous marine bacterium Vibrio fischeri and has been used to study determinants of symbiont specificity, the influence of symbiosis on development of the squid light organ, and the mechanisms by which a stable association is achieved. Both partners can be grown independently under laboratory conditions, a feature that offers the unusual opportunity to manipulate the symbiosis experimentally. Molecular and genetic tools have been developed for V. fischeri, and a large expressed sequence tag (EST) database is available for the host symbiotic tissues. Additionally, comparisons between light organ form and function to those of the eye can be made. Both types of tissue interact with light, but have divergent embryonic development. As such, they offer an opportunity to study the molecular basis for the evolution of morphological novelties.},
}
@article {pmid20133870,
year = {2010},
author = {Wier, AM and Nyholm, SV and Mandel, MJ and Massengo-Tiassé, RP and Schaefer, AL and Koroleva, I and Splinter-Bondurant, S and Brown, B and Manzella, L and Snir, E and Almabrazi, H and Scheetz, TE and Bonaldo, Mde F and Casavant, TL and Soares, MB and Cronan, JE and Reed, JL and Ruby, EG and McFall-Ngai, MJ},
title = {Transcriptional patterns in both host and bacterium underlie a daily rhythm of anatomical and metabolic change in a beneficial symbiosis.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {107},
number = {5},
pages = {2259-2264},
doi = {10.1073/pnas.0909712107},
pmid = {20133870},
issn = {1091-6490},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; R01 AI015650/AI/NIAID NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01-AI15650/AI/NIAID NIH HHS/United States ; F32 GM078760/GM/NIGMS NIH HHS/United States ; R01-AI50661/AI/NIAID NIH HHS/United States ; R01-RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*genetics/*metabolism/ultrastructure ; Anaerobiosis ; Animals ; Chitin/metabolism ; Circadian Rhythm/genetics/physiology ; Decapodiformes/anatomy & histology/*genetics/metabolism/*microbiology ; Diet ; Gene Expression Profiling ; Genes, Bacterial ; Lipid Metabolism ; Microscopy, Electron, Transmission ; Models, Biological ; Molecular Sequence Data ; Oligonucleotide Array Sequence Analysis ; Symbiosis/*genetics/*physiology ; },
abstract = {Mechanisms for controlling symbiont populations are critical for maintaining the associations that exist between a host and its microbial partners. We describe here the transcriptional, metabolic, and ultrastructural characteristics of a diel rhythm that occurs in the symbiosis between the squid Euprymna scolopes and the luminous bacterium Vibrio fischeri. The rhythm is driven by the host's expulsion from its light-emitting organ of most of the symbiont population each day at dawn. The transcriptomes of both the host epithelium that supports the symbionts and the symbiont population itself were characterized and compared at four times over this daily cycle. The greatest fluctuation in gene expression of both partners occurred as the day began. Most notable was an up-regulation in the host of >50 cytoskeleton-related genes just before dawn and their subsequent down-regulation within 6 h. Examination of the epithelium by TEM revealed a corresponding restructuring, characterized by effacement and blebbing of its apical surface. After the dawn expulsion, the epithelium reestablished its polarity, and the residual symbionts began growing, repopulating the light organ. Analysis of the symbiont transcriptome suggested that the bacteria respond to the effacement by up-regulating genes associated with anaerobic respiration of glycerol; supporting this finding, lipid analysis of the symbionts' membranes indicated a direct incorporation of host-derived fatty acids. After 12 h, the metabolic signature of the symbiont population shifted to one characteristic of chitin fermentation, which continued until the following dawn. Thus, the persistent maintenance of the squid-vibrio symbiosis is tied to a dynamic diel rhythm that involves both partners.},
}
@article {pmid20061475,
year = {2010},
author = {Bassis, CM and Visick, KL},
title = {The cyclic-di-GMP phosphodiesterase BinA negatively regulates cellulose-containing biofilms in Vibrio fischeri.},
journal = {Journal of bacteriology},
volume = {192},
number = {5},
pages = {1269-1278},
doi = {10.1128/JB.01048-09},
pmid = {20061475},
issn = {1098-5530},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; R01 GM059690-10/GM/NIGMS NIH HHS/United States ; R01 GM59690/GM/NIGMS NIH HHS/United States ; R01 GM059690-11/GM/NIGMS NIH HHS/United States ; R01 GM059690-09/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Amino Acid Substitution ; Animals ; Bacterial Proteins/genetics/*metabolism ; Benzenesulfonates/metabolism ; Biofilms/*growth & development ; Cellulose/metabolism ; Coloring Agents/metabolism ; Congo Red/metabolism ; Cyclic GMP/*analogs & derivatives/metabolism ; DNA Transposable Elements ; Down-Regulation ; Fluorescent Dyes/metabolism ; Gene Knockout Techniques ; Gene Order ; Mutagenesis, Insertional ; Mutagenesis, Site-Directed ; Phosphoric Diester Hydrolases/genetics/*metabolism ; Staining and Labeling ; },
abstract = {Bacteria produce different types of biofilms under distinct environmental conditions. Vibrio fischeri has the capacity to produce at least two distinct types of biofilms, one that relies on the symbiosis polysaccharide Syp and another that depends upon cellulose. A key regulator of biofilm formation in bacteria is the intracellular signaling molecule cyclic diguanylate (c-di-GMP). In this study, we focused on a predicted c-di-GMP phosphodiesterase encoded by the gene binA, located directly downstream of syp, a cluster of 18 genes critical for biofilm formation and the initiation of symbiotic colonization of the squid Euprymna scolopes. Disruption or deletion of binA increased biofilm formation in culture and led to increased binding of Congo red and calcofluor, which are indicators of cellulose production. Using random transposon mutagenesis, we determined that the phenotypes of the DeltabinA mutant strain could be disrupted by insertions in genes in the bacterial cellulose biosynthesis cluster (bcs), suggesting that cellulose production is negatively regulated by BinA. Replacement of critical amino acids within the conserved EAL residues of the EAL domain disrupted BinA activity, and deletion of binA increased c-di-GMP levels in the cell. Together, these data support the hypotheses that BinA functions as a phosphodiesterase and that c-di-GMP activates cellulose biosynthesis. Finally, overexpression of the syp regulator sypG induced binA expression. Thus, this work reveals a mechanism by which V. fischeri inhibits cellulose-dependent biofilm formation and suggests that the production of two different polysaccharides may be coordinated through the action of the cellulose inhibitor BinA.},
}
@article {pmid20036144,
year = {2010},
author = {McFall-Ngai, M and Nyholm, SV and Castillo, MG},
title = {The role of the immune system in the initiation and persistence of the Euprymna scolopes--Vibrio fischeri symbiosis.},
journal = {Seminars in immunology},
volume = {22},
number = {1},
pages = {48-53},
doi = {10.1016/j.smim.2009.11.003},
pmid = {20036144},
issn = {1096-3618},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01-AI50661/AI/NIAID NIH HHS/United States ; RR R01-12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*immunology/metabolism ; Animals ; Decapodiformes/*immunology/metabolism ; Humans ; *Immune System ; Immunity, Innate ; Signal Transduction ; *Symbiosis ; },
abstract = {The squid-vibrio symbiosis is an experimental system being studied as a model of the chronic colonization of animal epithelia by bacterial partners. One principal question being asked with this model is: what is the role of the immune system in the dynamics of the onset and maintenance of the symbiotic state? This review focuses upon results of research to date, which have demonstrated that both cell-mediated and cell-free components of the innate immune system are involved in these processes.},
}
@article {pmid19818022,
year = {2009},
author = {Visick, KL},
title = {An intricate network of regulators controls biofilm formation and colonization by Vibrio fischeri.},
journal = {Molecular microbiology},
volume = {74},
number = {4},
pages = {782-789},
doi = {10.1111/j.1365-2958.2009.06899.x},
pmid = {19818022},
issn = {1365-2958},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; R01 GM059690-08/GM/NIGMS NIH HHS/United States ; R01 GM059690-09/GM/NIGMS NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/growth & development/pathogenicity/*physiology ; Animals ; Bacterial Proteins/metabolism ; Biofilms/*growth & development ; Decapodiformes/*microbiology ; *Gene Expression Regulation, Bacterial ; Regulon ; Transcription Factors/metabolism ; Vibrio Infections/microbiology/*veterinary ; Virulence Factors/metabolism ; },
abstract = {The initial encounter between a microbe and its host can dictate the success of the interaction, be it symbiosis or pathogenesis. This is the case, for example, in the symbiosis between the bacterium Vibrio fischeri and the squid Euprymna scolopes, which proceeds via a biofilm-like bacterial aggregation, followed by entry and growth. A key regulator, the sensor kinase RscS, is critical for symbiotic biofilm formation and colonization. When introduced into a fish symbiont strain that naturally lacks the rscS gene and cannot colonize squid, RscS permits colonization, thereby extending the host range of these bacteria. RscS controls biofilm formation by inducing transcription of the symbiosis polysaccharide (syp) gene locus. Transcription of syp also requires the sigma(54)-dependent activator SypG, which functions downstream of RscS. In addition to these regulators, SypE, a response regulator that lacks an apparent DNA binding domain, exerts both positive and negative control over biofilm formation. The putative sensor kinase SypF and the putative response regulator VpsR, both of which contribute to control of cellulose production, also influence biofilm formation. The wealth of regulators and the correlation between biofilm formation and colonization adds to the already considerable utility of the V. fischeri-E. scolopes model system.},
}
@article {pmid19686342,
year = {2009},
author = {Ariyakumar, DS and Nishiguchi, MK},
title = {Characterization of two host-specific genes, mannose-sensitive hemagglutinin (mshA) and uridyl phosphate dehydrogenase (UDPDH) that are involved in the Vibrio fischeri-Euprymna tasmanica mutualism.},
journal = {FEMS microbiology letters},
volume = {299},
number = {1},
pages = {65-73},
doi = {10.1111/j.1574-6968.2009.01732.x},
pmid = {19686342},
issn = {1574-6968},
support = {SC1 AI081659-01/AI/NIAID NIH HHS/United States ; S06 GM008136/GM/NIGMS NIH HHS/United States ; SC1 AI081659-02/AI/NIAID NIH HHS/United States ; SO6 GM008136-32S2-1/GM/NIGMS NIH HHS/United States ; 1SC1AI081659-01/AI/NIAID NIH HHS/United States ; SC1 AI081659/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/enzymology/genetics/isolation & purification/*physiology ; Animals ; Bacterial Proteins/genetics/*metabolism ; Decapodiformes/*microbiology/*physiology ; Hemagglutinins/genetics/*metabolism ; Host Specificity ; Mannose-Binding Lectin/genetics/*metabolism ; Mutation ; *Symbiosis ; Uridine Diphosphate Glucose Dehydrogenase/genetics/*metabolism ; },
abstract = {While much has been known about the mutualistic associations between the sepiolid squid Euprymna tasmanica and the luminescent bacterium, Vibrio fischeri, less is known about the connectivity between the microscopic and molecular basis of initial attachment and persistence in the light organ. Here, we examine the possible effects of two symbiotic genes on specificity and biofilm formation of V. fischeri in squid light organs. Uridine diphosphate glucose-6-dehydrogenase (UDPDH) and mannose-sensitive hemagglutinin (mshA) mutants were generated in V. fischeri to determine whether each gene has an effect on host colonization, specificity, and biofilm formation. Both squid light organ colonization assays and transmission electron microscopy confirmed differences in host colonization between wild-type and mutant strains, and also demonstrated the importance of both UDPDH and mshA gene expression for successful light organ colonization. This furthers our understanding of the genetic factors playing important roles in this environmentally transmitted symbiosis.},
}
@article {pmid19416268,
year = {2009},
author = {Troll, JV and Adin, DM and Wier, AM and Paquette, N and Silverman, N and Goldman, WE and Stadermann, FJ and Stabb, EV and McFall-Ngai, MJ},
title = {Peptidoglycan induces loss of a nuclear peptidoglycan recognition protein during host tissue development in a beneficial animal-bacterial symbiosis.},
journal = {Cellular microbiology},
volume = {11},
number = {7},
pages = {1114-1127},
doi = {10.1111/j.1462-5822.2009.01315.x},
pmid = {19416268},
issn = {1462-5822},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; AI55397/AI/NIAID NIH HHS/United States ; R01 AI050661-07/AI/NIAID NIH HHS/United States ; T32 AI055397/AI/NIAID NIH HHS/United States ; R01-AI50661/AI/NIAID NIH HHS/United States ; R01-RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*immunology/*physiology ; Amino Acid Sequence ; Animals ; Apoptosis ; Carrier Proteins/*immunology/metabolism ; Cell Nucleus/chemistry ; Decapodiformes/*immunology/*microbiology ; Epithelial Cells/chemistry/microbiology ; Gene Deletion ; Microscopy, Fluorescence ; Molecular Sequence Data ; Peptidoglycan/genetics/*immunology/metabolism ; *Symbiosis ; },
abstract = {Peptidoglycan recognition proteins (PGRPs) are mediators of innate immunity and recently have been implicated in developmental regulation. To explore the interplay between these two roles, we characterized a PGRP in the host squid Euprymna scolopes (EsPGRP1) during colonization by the mutualistic bacterium Vibrio fischeri. Previous research on the squid-vibrio symbiosis had shown that, upon colonization of deep epithelium-lined crypts of the host light organ, symbiont-derived peptidoglycan monomers induce apoptosis-mediated regression of remote epithelial fields involved in the inoculation process. In this study, immunofluorescence microscopy revealed that EsPGRP1 localizes to the nuclei of epithelial cells, and symbiont colonization induces the loss of EsPGRP1 from apoptotic nuclei. The loss of nuclear EsPGRP1 occurred prior to DNA cleavage and breakdown of the nuclear membrane, but followed chromatin condensation, suggesting that it occurs during late-stage apoptosis. Experiments with purified peptidoglycan monomers and with V. fischeri mutants defective in peptidoglycan-monomer release provided evidence that these molecules trigger nuclear loss of EsPGRP1 and apoptosis. The demonstration of a nuclear PGRP is unprecedented, and the dynamics of EsPGRP1 during apoptosis provide a striking example of a connection between microbial recognition and developmental responses in the establishment of symbiosis.},
}
@article {pmid19196278,
year = {2009},
author = {Nyholm, SV and Stewart, JJ and Ruby, EG and McFall-Ngai, MJ},
title = {Recognition between symbiotic Vibrio fischeri and the haemocytes of Euprymna scolopes.},
journal = {Environmental microbiology},
volume = {11},
number = {2},
pages = {483-493},
doi = {10.1111/j.1462-2920.2008.01788.x},
pmid = {19196278},
issn = {1462-2920},
support = {AI-50661/AI/NIAID NIH HHS/United States ; R01 AI050661/AI/NIAID NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01 RR012294-11/RR/NCRR NIH HHS/United States ; RR-12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*immunology/*physiology ; Animals ; Bacterial Outer Membrane Proteins/genetics/immunology ; Decapodiformes/*immunology/*microbiology ; Gene Deletion ; Hemocytes/*immunology/*microbiology ; Phagocytosis ; *Symbiosis ; },
abstract = {The light organ crypts of the squid Euprymna scolopes permit colonization exclusively by the luminous bacterium Vibrio fischeri. Because the crypt interior remains in contact with seawater, the squid must not only foster the specific symbiosis, but also continue to exclude other bacteria. Investigation of the role of the innate immune system in these processes revealed that macrophage-like haemocytes isolated from E. scolopes recognized and phagocytosed V. fischeri less than other closely related bacterial species common to the host's environment. Interestingly, phagocytes isolated from hosts that had been cured of their symbionts bound five times more V. fischeri cells than those from uncured hosts. No such change in the ability to bind other species of bacteria was observed, suggesting that the host adapts specifically to V. fischeri. Deletion of the gene encoding OmpU, the major outer membrane protein of V. fischeri, increased binding by haemocytes from uncured animals to the level observed for haemocytes from cured animals. Co-incubation with wild-type V. fischeri reduced this binding, suggesting that they produce a factor that complements the mutant's defect. Analyses of the phagocytosis of bound cells by fluorescence-activated cell sorting indicated that once binding to haemocytes had occurred, V. fischeri cells are phagocytosed as effectively as other bacteria. Thus, discrimination by this component of the squid immune system occurs at the level of haemocyte binding, and this response: (i) is modified by previous exposure to the symbiont and (ii) relies on outer membrane and/or secreted components of the symbionts. These data suggest that regulation of host haemocyte binding by the symbiont may be one of many factors that contribute to specificity in this association.},
}
@article {pmid19182778,
year = {2009},
author = {Mandel, MJ and Wollenberg, MS and Stabb, EV and Visick, KL and Ruby, EG},
title = {A single regulatory gene is sufficient to alter bacterial host range.},
journal = {Nature},
volume = {458},
number = {7235},
pages = {215-218},
doi = {10.1038/nature07660},
pmid = {19182778},
issn = {1476-4687},
support = {T32 GM007215/GM/NIGMS NIH HHS/United States ; R01 GM059690-08/GM/NIGMS NIH HHS/United States ; F32 GM078760-03/GM/NIGMS NIH HHS/United States ; R01 GM059690/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01 GM059690-07/GM/NIGMS NIH HHS/United States ; F32 GM078760/GM/NIGMS NIH HHS/United States ; R01 RR012294-13/RR/NCRR NIH HHS/United States ; T32 GM007215-33/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*genetics/*growth & development ; Animal Structures/microbiology ; Animals ; Biofilms/growth & development ; Decapodiformes/*microbiology ; Molecular Sequence Data ; Pacific Ocean ; Phylogeny ; Polysaccharides, Bacterial/genetics/metabolism ; Protein Kinases/genetics/metabolism ; Symbiosis/genetics/*physiology ; },
abstract = {Microbial symbioses are essential for the normal development and growth of animals. Often, symbionts must be acquired from the environment during each generation, and identification of the relevant symbiotic partner against a myriad of unwanted relationships is a formidable task. Although examples of this specificity are well-documented, the genetic mechanisms governing it are poorly characterized. Here we show that the two-component sensor kinase RscS is necessary and sufficient for conferring efficient colonization of Euprymna scolopes squid by bioluminescent Vibrio fischeri from the North Pacific Ocean. In the squid symbiont V. fischeri ES114, RscS controls light-organ colonization by inducing the Syp exopolysaccharide, a mediator of biofilm formation during initial infection. A genome-level comparison revealed that rscS, although present in squid symbionts, is absent from the fish symbiont V. fischeri MJ11. We found that heterologous expression of RscS in strain MJ11 conferred the ability to colonize E. scolopes in a manner comparable to that of natural squid isolates. Furthermore, phylogenetic analyses support an important role for rscS in the evolution of the squid symbiosis. Our results demonstrate that a regulatory gene can alter the host range of animal-associated bacteria. We show that, by encoding a regulator and not an effector that interacts directly with the host, a single gene can contribute to the evolution of host specificity by switching 'on' pre-existing capabilities for interaction with animal tissue.},
}
@article {pmid19151142,
year = {2009},
author = {Nyholm, SV},
title = {Peptidoglycan monomer release and Vibrio fischeri.},
journal = {Journal of bacteriology},
volume = {191},
number = {7},
pages = {1997-1999},
doi = {10.1128/JB.01801-08},
pmid = {19151142},
issn = {1098-5530},
mesh = {Aliivibrio fischeri/chemistry/*metabolism ; Animals ; Decapodiformes/growth & development/*microbiology ; Morphogenesis ; Peptidoglycan/chemistry/*metabolism ; },
}
@article {pmid21152248,
year = {2009},
author = {Guerrero-Ferreira, RC and Nishiguchi, MK},
title = {ULTRASTRUCTURE OF LIGHT ORGANS OF LOLIGINID SQUIDS AND THEIR BACTERIAL SYMBIONTS: A NOVEL MODEL SYSTEM FOR THE STUDY OF MARINE SYMBIOSES.},
journal = {Vie et milieu (Paris, France : 1980)},
volume = {59},
number = {3-4},
pages = {307-313},
pmid = {21152248},
issn = {0240-8759},
support = {SC1 AI081659/AI/NIAID NIH HHS/United States ; SC1 AI081659-01/AI/NIAID NIH HHS/United States ; SC1 AI081659-02/AI/NIAID NIH HHS/United States ; },
abstract = {The class Cephalopoda (Phylum Mollusca), encompassing squids and octopuses, contains multiple species that are characterized by the presence of specialized organs known to emit light. These complex organs have a variety of morphological characteristics ranging from groups of simple, light-producing cells, to highly specialized organs (light organs) with cells surrounded by reflectors, lenses, light guides, color filters, and muscles. Bacteriogenic light organs have been well characterized in sepiolid squids, but a number of species in the family Loliginidae are also known to contain bacteriogenic light organs. Interest in loliginid light organ structure has recently arisen because of their potential as ecological niches for Vibrio harveyi, a pathogenic marine bacterium. This also implies the importance of loliginid light organs as reservoirs for V. harveyi persistence in the ocean. The present study utilized transmission and scanning electron microscopy to characterize the morphology of loliginid light organs and determined the location of bacterial symbiont cells within the tissue. It was determined that the rod-shaped loliginid symbionts lack flagella, as similarly observed in other light organ-associated bacteria. Also, the interaction of individual cells to light organ tissue is not as defined as reported for other squid-Vibrio systems. In addition, SEM observations show the presence of two pores leading to the bacterial chamber. Data presented here offer support for the hypothesis of environmental transfer of bacterial symbionts in loliginid squids.},
}
@article {pmid20725603,
year = {2009},
author = {Nair, V and Nishiguchi, MK},
title = {BIOLOGICAL PROPERTIES (IN VITRO) EXHIBITED BY FREE-LIVING AND SYMBIOTIC VIBRIO ISOLATES.},
journal = {Vie et milieu (Paris, France : 1980)},
volume = {59},
number = {3-4},
pages = {277-285},
pmid = {20725603},
issn = {0240-8759},
support = {SC1 AI081659-01/AI/NIAID NIH HHS/United States ; R25 GM048998/GM/NIGMS NIH HHS/United States ; S06 GM008136/GM/NIGMS NIH HHS/United States ; SC1 AI081659-02/AI/NIAID NIH HHS/United States ; SC1 AI081659/AI/NIAID NIH HHS/United States ; },
abstract = {Adhesion and biofilm forming ability of symbiotic bacteria play a crucial role in host colonization and tissue infection. Bacteria benefit by adhering to their host in a manner that allows them to successfully maintain contact for the exchange of nutrients, hormones, or other necessary products. This study examined pili morphology, motility, and biofilm formation exhibited by Vibrio fischeri strains (free-living and symbiotic). Since these symbiotic factors contribute in some fashion to the interaction between V. fischeri and their squid host, variation between strains may be a contributing factor that leads to specificity among different hosts. V. fischeri strains examined in this study demonstrated considerable variation in their biological properties when observed in vitro. In addition to differences observed between strains isolated from several different host species, we observed variation between strains isolated from the same host species from diverse geographical locations. This study suggests that subtle differences in the biological properties of closely related V. fischeri strains may influence the nature of the interaction among V. fischeri and their sepiolid hosts.},
}
@article {pmid19074387,
year = {2009},
author = {Adin, DM and Engle, JT and Goldman, WE and McFall-Ngai, MJ and Stabb, EV},
title = {Mutations in ampG and lytic transglycosylase genes affect the net release of peptidoglycan monomers from Vibrio fischeri.},
journal = {Journal of bacteriology},
volume = {191},
number = {7},
pages = {2012-2022},
doi = {10.1128/JB.01547-08},
pmid = {19074387},
issn = {1098-5530},
support = {A150661//PHS HHS/United States ; },
mesh = {Aliivibrio fischeri/chemistry/*genetics/*metabolism ; Animals ; Bacterial Proteins/*genetics/metabolism ; Decapodiformes/growth & development/microbiology ; Glycosyltransferases/*genetics/metabolism ; Light ; Membrane Transport Proteins/*genetics/metabolism ; Morphogenesis ; Multigene Family ; *Mutation ; Peptidoglycan/chemistry/*metabolism ; },
abstract = {The light-organ symbiont Vibrio fischeri releases N-acetylglucosaminyl-1,6-anhydro-N-acetylmuramylalanyl-gamma-glutamyldiaminopimelylalanine, a disaccharide-tetrapeptide component of peptidoglycan that is referred to here as "PG monomer." In contrast, most gram-negative bacteria recycle PG monomer efficiently, and it does not accumulate extracellularly. PG monomer can stimulate normal light-organ morphogenesis in the host squid Euprymna scolopes, resulting in regression of ciliated appendages similar to that triggered by infection with V. fischeri. We examined whether the net release of PG monomers by V. fischeri resulted from lytic transglycosylase activity or from defects in AmpG, the permease through which PG monomers enter the cytoplasm for recycling. An ampG mutant displayed a 100-fold increase in net PG monomer release, indicating that AmpG is functional. The ampG mutation also conferred the uncharacteristic ability to induce light-organ morphogenesis even when placed in a nonmotile flaJ mutant that cannot infect the light-organ crypts. We targeted five potential lytic transglycosylase genes singly and in specific combinations to assess their role in PG monomer release. Combinations of mutations in ltgA, ltgD, and ltgY decreased net PG monomer release, and a triple mutant lacking all three of these genes had little to no accumulation of PG monomers in culture supernatants. This mutant colonized the host as well as the wild type did; however, the mutant-infected squid were more prone to later superinfection by a second V. fischeri strain. We propose that the lack of PG monomer release by this mutant results in less regression of the infection-promoting ciliated appendages, leading to this propensity for superinfection.},
}
@article {pmid19036327,
year = {2008},
author = {McFall-Ngai, M},
title = {Hawaiian bobtail squid.},
journal = {Current biology : CB},
volume = {18},
number = {22},
pages = {R1043-4},
doi = {10.1016/j.cub.2008.08.059},
pmid = {19036327},
issn = {0960-9822},
mesh = {Aliivibrio fischeri/*physiology ; Animals ; Behavior, Animal ; Decapodiformes/anatomy & histology/*microbiology/physiology ; *Symbiosis ; },
}
@article {pmid18997024,
year = {2009},
author = {Wollenberg, MS and Ruby, EG},
title = {Population structure of Vibrio fischeri within the light organs of Euprymna scolopes squid from Two Oahu (Hawaii) populations.},
journal = {Applied and environmental microbiology},
volume = {75},
number = {1},
pages = {193-202},
doi = {10.1128/AEM.01792-08},
pmid = {18997024},
issn = {1098-5336},
support = {R01 RR012294/RR/NCRR NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*classification/*genetics/isolation & purification/physiology ; Animal Structures/*microbiology ; Animals ; Bacterial Typing Techniques ; *Biodiversity ; Cluster Analysis ; DNA Fingerprinting ; DNA, Bacterial/genetics ; Decapodiformes/*microbiology ; Genotype ; Hawaii ; Models, Theoretical ; Phenotype ; Symbiosis ; },
abstract = {We resolved the intraspecific diversity of Vibrio fischeri, the bioluminescent symbiont of the Hawaiian sepiolid squid Euprymna scolopes, at two previously unexplored morphological and geographical scales. These scales ranged from submillimeter regions within the host light organ to the several kilometers encompassing two host populations around Oahu. To facilitate this effort, we employed both novel and standard genetic and phenotypic assays of light-organ symbiont populations. A V. fischeri-specific fingerprinting method and five phenotypic assays were used to gauge the genetic richness of V. fischeri populations; these methods confirmed that the symbiont population present in each adult host's light organ is polyclonal. Upon statistical analysis of these genetic and phenotypic population data, we concluded that the characteristics of symbiotic populations were more similar within individual host populations than between the two distinct Oahu populations of E. scolopes, providing evidence that local geographic symbiont population structure exists. Finally, to better understand the genesis of symbiont diversity within host light organs, the process of symbiosis initiation in newly hatched juvenile squid was examined both experimentally and by mathematical modeling. We concluded that, after the juvenile hatches, only one or two cells of V. fischeri enter each of six internal epithelium-lined crypts present in the developing light organ. We hypothesize that the expansion of different, crypt-segregated, clonal populations creates the polyclonal adult light-organ population structure observed in this study. The stability of the luminous-bacterium-sepiolid squid mutualism in the presence of a polyclonal symbiont population structure is discussed in the context of contemporary evolutionary theory.},
}
@article {pmid18841707,
year = {2008},
author = {McFall-Ngai, M},
title = {Host-microbe symbiosis: the squid-Vibrio association--a naturally occurring, experimental model of animal/bacterial partnerships.},
journal = {Advances in experimental medicine and biology},
volume = {635},
number = {},
pages = {102-112},
doi = {10.1007/978-0-387-09550-9_9},
pmid = {18841707},
issn = {0065-2598},
mesh = {Animals ; Decapodiformes/growth & development/*microbiology ; *Host-Pathogen Interactions ; Luminescence ; *Models, Biological ; *Symbiosis ; Vibrio/cytology/*physiology ; },
abstract = {Many, if not most, animals have specific symbiotic relationships with bacterial partners. Recent studies suggest that vertebrates create alliances with highly complex consortia of hundreds to thousands of prokaryotic phylotypes. In contrast, invertebrates often have binary associations, i.e., relationships with a population of a single bacterial species. In this chapter, the association between the Hawaiian sepiolid squid Euprymna scolopes and the marine luminous bacterium Vibrio fisheri is highlighted. This symbiosis offers a relatively simple, yet naturally occurring, association that can be experimentally manipulated. Studies of this system are providing insight into the precise mechanisms by which a beneficial animal-bacterial symbiosis can be established and maintained.},
}
@article {pmid18682555,
year = {2008},
author = {Chun, CK and Troll, JV and Koroleva, I and Brown, B and Manzella, L and Snir, E and Almabrazi, H and Scheetz, TE and Bonaldo, Mde F and Casavant, TL and Soares, MB and Ruby, EG and McFall-Ngai, MJ},
title = {Effects of colonization, luminescence, and autoinducer on host transcription during development of the squid-vibrio association.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {105},
number = {32},
pages = {11323-11328},
doi = {10.1073/pnas.0802369105},
pmid = {18682555},
issn = {1091-6490},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01-AI50661/AI/NIAID NIH HHS/United States ; R01-RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Animals ; Base Sequence ; Decapodiformes/microbiology/*physiology ; Epithelium/microbiology/physiology ; Gene Expression Regulation, Bacterial/*physiology ; Genes, Bacterial/*physiology ; *Luminescence ; Mice ; Molecular Sequence Data ; Specific Pathogen-Free Organisms/physiology ; Symbiosis/*physiology ; Zebrafish ; },
abstract = {The light-organ symbiosis between the squid Euprymna scolopes and the luminous bacterium Vibrio fischeri offers the opportunity to decipher the hour-by-hour events that occur during the natural colonization of an animal's epithelial surface by its microbial partners. To determine the genetic basis of these events, a glass-slide microarray was used to characterize the light-organ transcriptome of juvenile squid in response to the initiation of symbiosis. Patterns of gene expression were compared between animals not exposed to the symbiont, exposed to the wild-type symbiont, or exposed to a mutant symbiont defective in either of two key characters of this association: bacterial luminescence or autoinducer (AI) production. Hundreds of genes were differentially regulated as a result of symbiosis initiation, and a hierarchy existed in the magnitude of the host's response to three symbiont features: bacterial presence > luminescence > AI production. Putative host receptors for bacterial surface molecules known to induce squid development are up-regulated by symbiont light production, suggesting that bioluminescence plays a key role in preparing the host for bacteria-induced development. Further, because the transcriptional response of tissues exposed to AI in the natural context (i.e., with the symbionts) differed from that to AI alone, the presence of the bacteria potentiates the role of quorum signals in symbiosis. Comparison of these microarray data with those from other symbioses, such as germ-free/conventionalized mice and zebrafish, revealed a set of shared genes that may represent a core set of ancient host responses conserved throughout animal evolution.},
}
@article {pmid18606737,
year = {2008},
author = {Dunn, AK and Stabb, EV},
title = {Genetic analysis of trimethylamine N-oxide reductases in the light organ symbiont Vibrio fischeri ES114.},
journal = {Journal of bacteriology},
volume = {190},
number = {17},
pages = {5814-5823},
doi = {10.1128/JB.00227-08},
pmid = {18606737},
issn = {1098-5530},
mesh = {Aliivibrio fischeri/*enzymology/genetics ; Animals ; Bacterial Proteins/*genetics ; Cytochrome P-450 Enzyme System/*genetics ; Decapodiformes/*microbiology ; Microscopy, Fluorescence ; Models, Genetic ; Operon/genetics ; Promoter Regions, Genetic/genetics ; Symbiosis/genetics ; },
abstract = {Trimethylamine N-oxide (TMAO) reductases are widespread in bacteria and often function in anaerobic respiration. The regulation and expression of TMAO reductase operons have been well studied in model genera such as Escherichia, Shewanella, and Rhodobacter, although TMAO reductases are present in many other bacteria, including the marine Vibrio species. The genome sequence of Vibrio fischeri revealed three putative TMAO reductase operons, and a previous report identified TMAO reductase activity in symbiotic V. fischeri isolates associated with the light organs of adult Hawaiian bobtail squid, Euprymna scolopes. We examined the roles and regulation of these three operons using mutational analyses and promoter-reporter fusions. We found that the torECA promoter, and to a lesser extent the torYZ and dmsABC promoters, were active during symbiotic colonization of juvenile E. scolopes; however, a V. fischeri strain lacking TMAO reductase activity displays no discernible colonization defect over the first 48 h. Our studies also revealed that torECA has the most active promoter of the putative TMAO reductase operons, and TorECA is the major contributor to TMAO-dependent growth in V. fischeri under the conditions tested. Interestingly, the transcriptional regulation of TMAO reductase operons in V. fischeri appears to differ from that in previously studied organisms, such as Escherichia coli, which may reflect differences in gene arrangement and bacterial habitat. This study lays the foundation for using V. fischeri as a model system for studying TMAO reductases in the Vibrionaceae.},
}
@article {pmid18587609,
year = {2009},
author = {Soto, W and Gutierrez, J and Remmenga, MD and Nishiguchi, MK},
title = {Salinity and temperature effects on physiological responses of Vibrio fischeri from diverse ecological niches.},
journal = {Microbial ecology},
volume = {57},
number = {1},
pages = {140-150},
doi = {10.1007/s00248-008-9412-9},
pmid = {18587609},
issn = {0095-3628},
support = {R25 GM061222/GM/NIGMS NIH HHS/United States ; SC1 AI081659-01/AI/NIAID NIH HHS/United States ; S06 GM008136/GM/NIGMS NIH HHS/United States ; GM-61222-01/GM/NIGMS NIH HHS/United States ; 52005881//Howard Hughes Medical Institute/United States ; S06 GM008136-32S2-1/GM/NIGMS NIH HHS/United States ; SC1 AI081659/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/growth & development/*isolation & purification/*physiology ; Animals ; Decapodiformes/classification/microbiology ; *Ecosystem ; Fishes/classification/microbiology ; Light ; *Salinity ; Seawater/microbiology ; Species Specificity ; Symbiosis ; *Temperature ; },
abstract = {Vibrio fischeri is a bioluminescent bacterial symbiont of sepiolid squids (Cephalopoda: Sepiolidae) and monocentrid fishes (Actinopterygii: Monocentridae). V. fischeri exhibit competitive dominance within the allopatrically distributed squid genus Euprymna, which have led to the evolution of V. fischeri host specialists. In contrast, the host genus Sepiola contains sympatric species that is thought to have given rise to V. fischeri that have evolved as host generalists. Given that these ecological lifestyles may have a direct effect upon the growth spectrum and survival limits in contrasting environments, optimal growth ranges were obtained for numerous V. fischeri isolates from both free-living and host environments. Upper and lower limits of growth were observed in sodium chloride concentrations ranging from 0.0% to 9.0%. Sepiola symbiotic isolates possessed the least variation in growth throughout the entire salinity gradient, whereas isolates from Euprymna were the least uniform at <2.0% NaCl. V. fischeri fish symbionts (CG101 and MJ101) and all free-living strains were the most dissimilar at >5.0% NaCl. Growth kinetics of symbiotic V. fischeri strains were also measured under a range of salinity and temperature combinations. Symbiotic V. fischeri ES114 and ET101 exhibited a synergistic effect for salinity and temperature, where significant differences in growth rates due to salinity existed only at low temperatures. Thus, abiotic factors such as temperature and salinity have differential effects between free-living and symbiotic strains of V. fischeri, which may alter colonization efficiency prior to infection.},
}
@article {pmid18523167,
year = {2008},
author = {Browne-Silva, J and Nishiguchi, MK},
title = {Gene sequences of the pil operon reveal relationships between symbiotic strains of Vibrio fischeri.},
journal = {International journal of systematic and evolutionary microbiology},
volume = {58},
number = {Pt 6},
pages = {1292-1299},
doi = {10.1099/ijs.0.65370-0},
pmid = {18523167},
issn = {1466-5026},
support = {SO6-GM0813626/GM/NIGMS NIH HHS/United States ; R25 GM048998/GM/NIGMS NIH HHS/United States ; GM0766724/GM/NIGMS NIH HHS/United States ; GM48998/GM/NIGMS NIH HHS/United States ; SC1 AI081659/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*classification/genetics ; Animals ; Bacterial Proteins/chemistry/genetics ; Decapodiformes/*microbiology ; Fimbriae Proteins/chemistry/*genetics ; Gene Order ; Molecular Sequence Data ; Operon/*genetics ; Phylogeny ; Seawater/microbiology ; Sequence Alignment ; *Sequence Analysis, DNA ; *Symbiosis ; },
abstract = {Symbiosis between the bobtail squid Euprymna scolopes (Mollusca: Cephalopoda) and Vibrio fischeri bacteria has been a well-studied model for understanding the molecular mechanisms of colonization and adherence to host cells. For example, pilin expression has been observed to cause subtle variation in colonization for a number of Gram-negative bacteria with eukaryotic hosts. To investigate variation amongst pil genes of closely related strains of vibrios, we amplified pil genes A, B, C and D to determine orientation and sequence similarity to other symbiotic vibrios. The pilA gene was found to be upstream from all other pil genes, and not contiguous with the rest of the operon. The pilB, pilC and pilD loci were flanked at the 3' end by yacE, followed by a conserved hypothetical gene. DNA sequences of each pil gene were aligned and analysed phylogenetically using parsimony for both individual and combined gene trees. Results demonstrate that certain pil loci (pilB and pilD) are conserved among strains of V. fischeri, but pilC differs in sequence between symbiotic and free-living strains. Phylogenetic analysis of all pil genes gives better resolution of Indo-west Pacific V. fischeri symbionts compared with analysis of the 16S rRNA gene. Hawaiian and Australian symbiotic strains form one monophyletic tree, supporting the hypothesis that V. fischeri strain specificity is selected by the geographical location of their hosts and is not related to specific squid species.},
}
@article {pmid18521572,
year = {2008},
author = {Bose, JL and Rosenberg, CS and Stabb, EV},
title = {Effects of luxCDABEG induction in Vibrio fischeri: enhancement of symbiotic colonization and conditional attenuation of growth in culture.},
journal = {Archives of microbiology},
volume = {190},
number = {2},
pages = {169-183},
doi = {10.1007/s00203-008-0387-1},
pmid = {18521572},
issn = {0302-8933},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; R01AI50661/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*growth & development/physiology ; Animals ; Bacterial Proteins/genetics/*metabolism ; Decapodiformes/*microbiology/*physiology ; *Gene Expression Regulation, Bacterial ; Luminescence ; Luminescent Proteins/genetics/*metabolism ; Mutation ; Operon ; *Symbiosis ; },
abstract = {Production of bioluminescence theoretically represents a cost, energetic or otherwise, that could slow Vibrio fischeri growth; however, bioluminescence is also thought to enable full symbiotic colonization of the Euprymna scolopes light organ by V. fischeri. Previous tests of these models have proven inconclusive, partly because they compared nonisogenic strains, or undefined and/or pleiotropic mutants. To test the influence of the bioluminescence-producing lux operon on growth and symbiotic competence, we generated dark luxCDABEG mutants in strains MJ1 and ES114 without disrupting the luxR-luxI regulatory circuit. The MJ1 luxCDABEG mutant out-competed its visibly luminescent parent approximately 26% per generation in a carbon-limited chemostat. Similarly, induction of luminescence in the otherwise dim ES114 strain slowed growth relative to DeltaluxCDABEG mutants. Some culture conditions yielded no detectable effect of luminescence on growth, indicating that luminescence is not always growth limiting; however, luminescence was never found to confer an advantage in culture. In contrast to this conditional disadvantage of lux expression, ES114 achieved approximately fourfold higher populations than its luxCDABEG mutant in the light organ of E. scolopes. These results demonstrate that induction of luxCDABEG can slow V. fischeri growth under certain culture conditions and is a positive symbiotic colonization factor.},
}
@article {pmid18510559,
year = {2008},
author = {Geszvain, K and Visick, KL},
title = {Multiple factors contribute to keeping levels of the symbiosis regulator RscS low.},
journal = {FEMS microbiology letters},
volume = {285},
number = {1},
pages = {33-39},
doi = {10.1111/j.1574-6968.2008.01209.x},
pmid = {18510559},
issn = {0378-1097},
support = {R01 GM059690-08/GM/NIGMS NIH HHS/United States ; R01 GM059690/GM/NIGMS NIH HHS/United States ; F32 GM073523-03/GM/NIGMS NIH HHS/United States ; R01 GM059690-07/GM/NIGMS NIH HHS/United States ; R01 GM059690-06A2/GM/NIGMS NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; F32 GM073523-02/GM/NIGMS NIH HHS/United States ; 1 F32 G073523//PHS HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*physiology ; Animals ; Bacterial Proteins/genetics/*metabolism ; Decapodiformes/*microbiology/physiology ; *Gene Expression Regulation, Bacterial ; Mutation, Missense ; Phenotype ; Promoter Regions, Genetic ; Protein Kinases/genetics/*metabolism ; *Symbiosis ; Transcription, Genetic ; },
abstract = {Increased activity alleles (rscS1 and rscS2) of the symbiosis regulator RscS induced both syp transcription and biofilm formation in Vibrio fischeri. Neither allele encodes a protein variant; instead they carry mutations near the putative ribosome-binding site and, in the case of rscS1, an additional silent mutation at codon Leu25. In this study, we found that endogenous levels of RscS are very low under the culture conditions examined and that the increased activity alleles dramatically increased the levels of protein. Of the two mutations present in rscS1, the Leu25 mutation, which replaces a rare with a more common Leu codon, appeared to make the greater contribution to increased activity. Our results suggest that RscS levels are maintained at low levels in the cell by the presence of a weak promoter, possible inefficient ribosome binding and the presence of rare codons in the 5' end of the gene. Restriction of RscS levels may be important to prevent spurious signalling by this sensor kinase in the absence of a squid host.},
}
@article {pmid18487409,
year = {2008},
author = {Adin, DM and Visick, KL and Stabb, EV},
title = {Identification of a cellobiose utilization gene cluster with cryptic beta-galactosidase activity in Vibrio fischeri.},
journal = {Applied and environmental microbiology},
volume = {74},
number = {13},
pages = {4059-4069},
doi = {10.1128/AEM.00190-08},
pmid = {18487409},
issn = {1098-5336},
support = {R01 GM059690-08/GM/NIGMS NIH HHS/United States ; R01 GM059690/GM/NIGMS NIH HHS/United States ; R01 GM059690-07/GM/NIGMS NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; AI50661/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*enzymology/genetics/growth & development ; Animals ; Bacterial Proteins/genetics/metabolism ; Cellobiose/*metabolism ; Computational Biology ; Culture Media ; Decapodiformes/microbiology ; *Multigene Family ; Symbiosis ; beta-Galactosidase/genetics/*metabolism ; },
abstract = {Cellobiose utilization is a variable trait that is often used to differentiate members of the family Vibrionaceae. We investigated how Vibrio fischeri ES114 utilizes cellobiose and found a cluster of genes required for growth on this beta-1,4-linked glucose disaccharide. This cluster includes genes annotated as a phosphotransferase system II (celA, celB, and celC), a glucokinase (celK), and a glucosidase (celG). Directly downstream of celCBGKA is celI, which encodes a LacI family regulator that represses cel transcription in the absence of cellobiose. When the celCBGKAI gene cluster was transferred to cellobiose-negative strains of Vibrio and Photobacterium, the cluster conferred the ability to utilize cellobiose. Genomic analyses of naturally cellobiose-positive Vibrio species revealed that V. salmonicida has a homolog of the celCBGKAI cluster, but V. vulnificus does not. Moreover, bioinformatic analyses revealed that CelG and CelK share the greatest homology with glucosidases and glucokinases in the phylum Firmicutes. These observations suggest that distinct genes for cellobiose utilization have been acquired by different lineages within the family Vibrionaceae. In addition, the loss of the celI regulator, but not the structural genes, attenuated the ability of V. fischeri to compete for colonization of its natural host, Euprymna scolopes, suggesting that repression of the cel gene cluster is important in this symbiosis. Finally, we show that the V. fischeri cellobioase (CelG) preferentially cleaves beta-d-glucose linkages but also cleaves beta-d-galactose-linked substrates such as 5-bromo-4-chloro-3-indolyl-beta-d-galactoside (X-gal), a finding that has important implications for the use of lacZ as a marker or reporter gene in V. fischeri.},
}
@article {pmid18487321,
year = {2008},
author = {Studer, SV and Mandel, MJ and Ruby, EG},
title = {AinS quorum sensing regulates the Vibrio fischeri acetate switch.},
journal = {Journal of bacteriology},
volume = {190},
number = {17},
pages = {5915-5923},
doi = {10.1128/JB.00148-08},
pmid = {18487321},
issn = {1098-5530},
support = {RR 12294/RR/NCRR NIH HHS/United States ; T32 GM007215/GM/NIGMS NIH HHS/United States ; T32 GM07215/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; F32 GM078760/GM/NIGMS NIH HHS/United States ; },
mesh = {Acetate-CoA Ligase/genetics/metabolism ; Acetates/*metabolism ; Acyl-Butyrolactones/metabolism ; Aliivibrio fischeri/genetics/growth & development/*metabolism ; Animals ; Bacterial Proteins/genetics/*metabolism/physiology ; Chromatography, High Pressure Liquid ; Decapodiformes/microbiology ; Gene Expression Regulation, Bacterial/drug effects ; Glucose/pharmacology ; Models, Biological ; Mutation ; *Quorum Sensing ; Repressor Proteins/genetics/metabolism/physiology ; Trans-Activators/genetics/metabolism/physiology ; },
abstract = {The marine bacterium Vibrio fischeri uses two acyl-homoserine lactone (acyl-HSL) quorum-sensing systems. The earlier signal, octanoyl-HSL, produced by AinS, is required for normal colonization of the squid Euprymna scolopes and, in culture, is necessary for a normal growth yield. In examining the latter requirement, we found that during growth in a glycerol/tryptone-based medium, wild-type V. fischeri cells initially excrete acetate but, in a metabolic shift termed the acetate switch, they subsequently utilize the acetate, removing it from the medium. In contrast, an ainS mutant strain grown in this medium does not remove the excreted acetate, which accumulates to lethal levels. The acetate switch is characterized by the induction of acs, the gene encoding acetyl coenzyme A (acetyl-CoA) synthetase, leading to uptake of the excreted acetate. Wild-type cells induce an acs transcriptional reporter 25-fold, coincident with the disappearance of the extracellular acetate; in contrast, the ainS mutant did not display significant induction of the acs reporter. Supplementation of the medium of an ainS mutant with octanoyl-HSL restored normal levels of acs induction and acetate uptake. Additional mutant analyses indicated that acs regulation was accomplished through the regulator LitR but was independent of the LuxIR quorum-signaling pathway. Importantly, the acs mutant of V. fischeri has a competitive defect when colonizing the squid, indicating the importance of proper control of acetate metabolism in the light of organ symbiosis. This is the first report of quorum-sensing control of the acetate switch, and it indicates a metabolic connection between acetate utilization and cell density.},
}
@article {pmid18469094,
year = {2008},
author = {Darnell, CL and Hussa, EA and Visick, KL},
title = {The putative hybrid sensor kinase SypF coordinates biofilm formation in Vibrio fischeri by acting upstream of two response regulators, SypG and VpsR.},
journal = {Journal of bacteriology},
volume = {190},
number = {14},
pages = {4941-4950},
doi = {10.1128/JB.00197-08},
pmid = {18469094},
issn = {1098-5530},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; R01 GM059690-07/GM/NIGMS NIH HHS/United States ; R01 GM059690-08/GM/NIGMS NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*physiology ; Animals ; Bacterial Adhesion ; Bacterial Proteins/genetics/*metabolism ; Biofilms/*growth & development ; Decapodiformes/microbiology ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Gene Order ; Multigene Family ; Mutation ; Protein Binding ; Protein Kinases/genetics/*metabolism ; Transcription Factors/genetics/metabolism ; },
abstract = {Colonization of the Hawaiian squid Euprymna scolopes by the marine bacterium Vibrio fischeri requires the symbiosis polysaccharide (syp) gene cluster, which contributes to symbiotic initiation by promoting biofilm formation on the surface of the symbiotic organ. We previously described roles for the syp-encoded response regulator SypG and an unlinked gene encoding the sensor kinase RscS in controlling syp transcription and inducing syp-dependent cell-cell aggregation phenotypes. Here, we report the involvement of an additional syp-encoded regulator, the putative sensor kinase SypF, in promoting biofilm formation. Through the isolation of an increased activity allele, sypF1, we determined that SypF can function to induce syp transcription as well as a variety of biofilm phenotypes, including wrinkled colony formation, adherence to glass, and pellicle formation. SypF1-mediated transcription of the syp cluster was entirely dependent on SypG. However, the biofilm phenotypes were reduced, not eliminated, in the sypG mutant. These phenotypes were also reduced in a mutant deleted for sypE, another syp-encoded response regulator. However, SypF1 still induced phenotypes in a sypG sypE double mutant, suggesting that SypF1 might activate another regulator(s). Our subsequent work revealed that the residual SypF1-induced biofilm formation depended on VpsR, a putative response regulator, and cellulose biosynthesis. These data support a model in which a network of regulators and at least two polysaccharide loci contribute to biofilm formation in V. fischeri.},
}
@article {pmid18441059,
year = {2008},
author = {Hussa, EA and Darnell, CL and Visick, KL},
title = {RscS functions upstream of SypG to control the syp locus and biofilm formation in Vibrio fischeri.},
journal = {Journal of bacteriology},
volume = {190},
number = {13},
pages = {4576-4583},
doi = {10.1128/JB.00130-08},
pmid = {18441059},
issn = {1098-5530},
support = {R01 GM059690-08/GM/NIGMS NIH HHS/United States ; R01 GM059690/GM/NIGMS NIH HHS/United States ; R01 GM059690-07/GM/NIGMS NIH HHS/United States ; R01 GM059690-06A2/GM/NIGMS NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*physiology ; Bacterial Adhesion/genetics/physiology ; Bacterial Proteins/genetics/*physiology ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Glass ; Mutation ; Polymerase Chain Reaction ; Transcription, Genetic ; },
abstract = {Two-component signal transduction systems, composed of sensor kinase (SK) and response regulator (RR) proteins, allow bacterial cells to adapt to changes such as environmental flux or the presence of a host. RscS is an SK required for Vibrio fischeri to initiate a symbiotic partnership with the Hawaiian squid Euprymna scolopes, likely due to its role in controlling the symbiosis polysaccharide (syp) genes and thus biofilm formation. To determine which RR(s) functions downstream of RscS, we performed epistasis experiments with a library of 35 RR mutants. We found that several RRs contributed to RscS-mediated biofilm formation in V. fischeri. However, only the syp-encoded symbiosis regulator SypG was required for both biofilm phenotypes and syp transcription induced by RscS. These data support the hypothesis that RscS functions upstream of SypG to induce biofilm formation. In addition, this work also revealed a role for the syp-encoded RR SypE in biofilm formation. To our knowledge, no other study has used a large-scale epistasis approach to elucidate two-component signaling pathways. Therefore, this work both contributes to our understanding of regulatory pathways important for symbiotic colonization by V. fischeri and establishes a paradigm for evaluating two-component pathways in the genomics era.},
}
@article {pmid18217861,
year = {2008},
author = {Dunn, AK and Stabb, EV},
title = {The twin arginine translocation system contributes to symbiotic colonization of Euprymna scolopes by Vibrio fischeri.},
journal = {FEMS microbiology letters},
volume = {279},
number = {2},
pages = {251-258},
doi = {10.1111/j.1574-6968.2007.01043.x},
pmid = {18217861},
issn = {0378-1097},
mesh = {Aliivibrio fischeri/genetics/*physiology ; Animals ; Artificial Gene Fusion ; Bacterial Proteins/genetics/*physiology ; Decapodiformes/*microbiology ; Gene Deletion ; Genes, Reporter ; Green Fluorescent Proteins/genetics/metabolism ; Membrane Transport Proteins/genetics/*physiology ; Virulence Factors/genetics/*physiology ; },
abstract = {In many bacteria, the twin arginine translocation (Tat) system transports folded proteins across the cytoplasmic membrane, and these proteins can play a role in symbiotic or pathogenic infections. A role for the Vibrio fischeri Tat system was identified during symbiotic colonization of its host Euprymna scolopes, demonstrating a function for the Tat system in host colonization by a member of the Vibrionaceae. Using bioinformatics, mutant analyses, and green fluorescent protein fusions, a set of Tat-targeted proteins in V. fischeri was identified.},
}
@article {pmid20414482,
year = {2008},
author = {Nyholm, SV and Nishiguchi, MK},
title = {THE EVOLUTIONARY ECOLOGY OF A SEPIOLID SQUID-VIBRIO ASSOCIATION: FROM CELL TO ENVIRONMENT.},
journal = {Vie et milieu (Paris, France : 1980)},
volume = {58},
number = {2},
pages = {175-184},
pmid = {20414482},
issn = {0240-8759},
support = {SC1 AI081659/AI/NIAID NIH HHS/United States ; SC1 AI081659-01/AI/NIAID NIH HHS/United States ; },
abstract = {Mutualistic relationships between bacteria and their eukaryotic hosts have existed for millions of years, and such associations can be used to understand the evolution of these beneficial partnerships. The symbiosis between sepiolid squids (Cephalopoda: Sepiolidae), and their Vibrio bacteria (gamma Proteobacteria: Vibrionaceae), has been a model system for over 20 years, giving insight as to the specificity of the association, and whether the interactions themselves give rise to such finely tuned dialog. Since the association is environmentally transmitted, selection for specificity can evolve from a number of factors; abiotic (temperature, salinity), as well as biotic (host species, receptors, cell/cell interactions). Here, we examine the transition between these forces effecting the symbiosis, and pose possible explanations as to why this association offers many attributes for understanding the role of symbiotic competence.},
}
@article {pmid18065606,
year = {2008},
author = {Adin, DM and Phillips, NJ and Gibson, BW and Apicella, MA and Ruby, EG and McFall-Ngai, MJ and Hall, DB and Stabb, EV},
title = {Characterization of htrB and msbB mutants of the light organ symbiont Vibrio fischeri.},
journal = {Applied and environmental microbiology},
volume = {74},
number = {3},
pages = {633-644},
doi = {10.1128/AEM.02138-07},
pmid = {18065606},
issn = {1098-5336},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; R01 AI50661/AI/NIAID NIH HHS/United States ; R01 RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Acyltransferases/*genetics/metabolism ; Aliivibrio fischeri/enzymology/genetics/growth & development/*physiology ; Animal Structures/*microbiology ; Animals ; Bacterial Proteins/genetics/metabolism ; Chromosomes, Bacterial/genetics ; Decapodiformes/anatomy & histology/*microbiology ; Light ; Lipid A/*metabolism ; *Mutation ; *Symbiosis ; },
abstract = {Bacterial lipid A is an important mediator of bacterium-host interactions, and secondary acylations added by HtrB and MsbB can be critical for colonization and virulence in pathogenic infections. In contrast, Vibrio fischeri lipid A stimulates normal developmental processes in this bacterium's mutualistic host, Euprymna scolopes, although the importance of lipid A structure in this symbiosis is unknown. To further examine V. fischeri lipid A and its symbiotic function, we identified two paralogs of htrB (designated htrB1 and htrB2) and an msbB gene in V. fischeri ES114 and demonstrated that these genes encode lipid A secondary acyltransferases. htrB2 and msbB are found on the Vibrio "housekeeping" chromosome 1 and are conserved in other Vibrio species. Mutations in htrB2 and msbB did not impair symbiotic colonization but resulted in phenotypic alterations in culture, including reduced motility and increased luminescence. These mutations also affected sensitivity to sodium dodecyl sulfate, kanamycin, and polymyxin, consistent with changes in membrane permeability. Conversely, htrB1 is located on the smaller, more variable vibrio chromosome 2, and an htrB1 mutant was wild-type-like in culture but appeared attenuated in initiating the symbiosis and was outcompeted 2.7-fold during colonization when mixed with the parent. These data suggest that htrB2 and msbB play conserved general roles in vibrio biology, whereas htrB1 plays a more symbiosis-specific role in V. fischeri.},
}
@article {pmid17933912,
year = {2008},
author = {Hunt, DE and Gevers, D and Vahora, NM and Polz, MF},
title = {Conservation of the chitin utilization pathway in the Vibrionaceae.},
journal = {Applied and environmental microbiology},
volume = {74},
number = {1},
pages = {44-51},
doi = {10.1128/AEM.01412-07},
pmid = {17933912},
issn = {1098-5336},
mesh = {Acetylglucosamine/metabolism ; Bacterial Proteins/genetics ; Chitin/*metabolism ; Chitinases/genetics ; Conserved Sequence ; DNA, Bacterial/chemistry/genetics ; Metabolic Networks and Pathways/*genetics ; Molecular Sequence Data ; Phylogeny ; Sequence Analysis, DNA ; Vibrionaceae/*genetics/growth & development/*metabolism ; },
abstract = {Vibrionaceae are regarded as important marine chitin degraders, and attachment to chitin regulates important biological functions; yet, the degree of chitin pathway conservation in Vibrionaceae is unknown. Here, a core chitin degradation pathway is proposed based on comparison of 19 Vibrio and Photobacterium genomes with a detailed metabolic map assembled for V. cholerae from published biochemical, genomic, and transcriptomic results. Further, to assess whether chitin degradation is a conserved property of Vibrionaceae, a set of 54 strains from 32 taxa were tested for the ability to grow on various forms of chitin. All strains grew on N-acetylglucosamine (GlcNAc), the monomer of chitin. The majority of isolates grew on alpha (crab shell) and beta (squid pen) chitin and contained chitinase A (chiA) genes. chiA sequencing and phylogenetic analysis suggest that this gene is a good indicator of chitin metabolism but appears subject to horizontal gene transfer and duplication. Overall, chitin metabolism appears to be a core function of Vibrionaceae, but individual pathway components exhibit dynamic evolutionary histories.},
}
@article {pmid22707847,
year = {2007},
author = {Guerrero-Ferreira, RC and Nishiguchi, MK},
title = {Biodiversity among luminescent symbionts from squid of the genera Uroteuthis, Loliolus and Euprymna (Mollusca: Cephalopoda).},
journal = {Cladistics : the international journal of the Willi Hennig Society},
volume = {23},
number = {5},
pages = {497-506},
doi = {10.1111/j.1096-0031.2007.00155.x},
pmid = {22707847},
issn = {0748-3007},
support = {S06 GM008136/GM/NIGMS NIH HHS/United States ; SC1 AI081659/AI/NIAID NIH HHS/United States ; },
abstract = {Luminescent bacteria in the family Vibrionaceae (Bacteria: γ-Proteobacteria) are commonly found in complex, bilobed light organs of sepiolid and loliginid squids. Although morphology of these organs in both families of squid is similar, the species of bacteria that inhabit each host has yet to be verified. We utilized sequences of 16S ribosomal RNA, luciferase α-subunit (luxA) and the glyceraldehyde-3-phosphate dehydrogenase (gapA) genes to determine phylogenetic relationships between 63 strains of Vibrio bacteria, which included representatives from different environments as well as unidentified luminescent isolates from loliginid and sepiolid squid from Thailand. A combined phylogenetic analysis was used including biochemical data such as carbon use, growth and luminescence. Results demonstrated that certain symbiotic Thai isolates found in the same geographic area were included in a clade containing bacterial species phenotypically suitable to colonize light organs. Moreover, multiple strains isolated from a single squid host were identified as more than one bacteria species in our phylogeny. This research presents evidence of species of luminescent bacteria that have not been previously described as symbiotic strains colonizing light organs of Indo-West Pacific loliginid and sepiolid squids, and supports the hypothesis of a non-species-specific association between certain sepiolid and loliginid squids and marine luminescent bacteria.},
}
@article {pmid17590235,
year = {2007},
author = {Bose, JL and Kim, U and Bartkowski, W and Gunsalus, RP and Overley, AM and Lyell, NL and Visick, KL and Stabb, EV},
title = {Bioluminescence in Vibrio fischeri is controlled by the redox-responsive regulator ArcA.},
journal = {Molecular microbiology},
volume = {65},
number = {2},
pages = {538-553},
doi = {10.1111/j.1365-2958.2007.05809.x},
pmid = {17590235},
issn = {0950-382X},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; AI21678/AI/NIAID NIH HHS/United States ; AI50661/AI/NIAID NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*metabolism ; Bacterial Proteins/genetics/*metabolism ; Base Sequence ; Binding Sites ; *Gene Expression Regulation, Bacterial ; *Luminescence ; Molecular Sequence Data ; Operon/*genetics ; Oxidation-Reduction ; Oxidative Stress ; Promoter Regions, Genetic ; Quorum Sensing/genetics ; Repressor Proteins/genetics/*metabolism ; },
abstract = {Bioluminescence generated by the Vibrio fischeri Lux system consumes oxygen and reducing power, and it has been proposed that cells use this to counteract either oxidative stress or the accumulation of excess reductant. These models predict that lux expression should respond to redox conditions; yet no redox-responsive regulator of lux is known. We found that the luxICDABEG operon responsible for bioluminescence is repressed by the ArcAB system, which is activated under reducing conditions. Consistent with a role for ArcAB in connecting redox monitoring to lux regulation, adding reductant decreased luminescence in an arc-dependent manner. ArcA binds to and regulates transcription from the luxICDABEG promoter, and it represses luminescence both in the bright strain MJ1 and in ES114, an isolate from the squid Euprymna scolopes that is not visibly luminescent in culture. In ES114, deleting arcA increased luminescence in culture approximately 500-fold to visible levels comparable to that of symbiotic cells. ArcA did not repress symbiotic luminescence, but by 48 h after inoculation, ArcA did contribute to colonization competitiveness. We hypothesize that inactivation of ArcA in response to oxidative stress during initial colonization derepresses luxICDABEG, but that ArcAB actively regulates other metabolic pathways in the more reduced environment of an established infection.},
}
@article {pmid17586650,
year = {2007},
author = {Hussa, EA and O'Shea, TM and Darnell, CL and Ruby, EG and Visick, KL},
title = {Two-component response regulators of Vibrio fischeri: identification, mutagenesis, and characterization.},
journal = {Journal of bacteriology},
volume = {189},
number = {16},
pages = {5825-5838},
doi = {10.1128/JB.00242-07},
pmid = {17586650},
issn = {0021-9193},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; GM 59690/GM/NIGMS NIH HHS/United States ; RR 12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/growth & development/*physiology ; Bacterial Proteins/genetics/*isolation & purification/physiology ; Gene Expression Regulation, Bacterial ; Genes, Regulator ; *Mutagenesis ; Signal Transduction/*physiology ; },
abstract = {Two-component signal transduction systems are utilized by prokaryotic and eukaryotic cells to sense and respond to environmental stimuli, both to maintain homeostasis and to rapidly adapt to changing conditions. Studies have begun to emerge that utilize a large-scale mutagenesis approach to analyzing these systems in prokaryotic organisms. Due to the recent availability of its genome sequence, such a global approach is now possible for the marine bioluminescent bacterium Vibrio fischeri, which exists either in a free-living state or as a mutualistic symbiont within a host organism such as the Hawaiian squid species Euprymna scolopes. In this work, we identified 40 putative two-component response regulators encoded within the V. fischeri genome. Based on the type of effector domain present, we classified six as NarL type, 13 as OmpR type, and six as NtrC type; the remaining 15 lacked a predicted DNA-binding domain. We subsequently mutated 35 of these genes via a vector integration approach and analyzed the resulting mutants for roles in bioluminescence, motility, and competitive colonization of squid. Through these assays, we identified three novel regulators of V. fischeri luminescence and seven regulators that altered motility. Furthermore, we found 11 regulators with a previously undescribed effect on competitive colonization of the host squid. Interestingly, five of the newly characterized regulators each affected two or more of the phenotypes examined, strongly suggesting interconnectivity among systems. This work represents the first large-scale mutagenesis of a class of genes in V. fischeri using a genomic approach and emphasizes the importance of two-component signal transduction in bacterium-host interactions.},
}
@article {pmid17473891,
year = {2006},
author = {Jones, BW and Nishiguchi, MK},
title = {Differentially expressed genes reveal adaptations between free-living and symbiotic niches of Vibrio fischeri in a fully established mutualism.},
journal = {Canadian journal of microbiology},
volume = {52},
number = {12},
pages = {1218-1227},
doi = {10.1139/w06-088},
pmid = {17473891},
issn = {0008-4166},
mesh = {Adaptation, Physiological/genetics/physiology ; Aliivibrio fischeri/*genetics/growth & development ; Animals ; Blotting, Southern ; DNA, Complementary/chemistry/genetics ; Decapodiformes/*microbiology ; Gene Expression Profiling ; *Gene Expression Regulation, Bacterial ; Gene Library ; Reverse Transcriptase Polymerase Chain Reaction ; Sequence Analysis, DNA ; Symbiosis/*genetics ; },
abstract = {A major force driving in the innovation of mutualistic symbioses is the number of adaptations that both organisms must acquire to provide overall increased fitness for a successful partnership. Many of these symbioses are relatively dependent on the ability of the symbiont to locate a host (specificity), as well as provide some novel capability upon colonization. The mutualism between sepiolid squids and members of the Vibrionaceae is a unique system in which development of the symbiotic partnership has been studied in detail, but much remains unknown about the genetics of symbiont colonization and persistence within the host. Using a method that captures exclusively expressed transcripts in either free-living or host-associated strains of Vibrio fischeri, we identified and verified expression of genes differentially expressed in both states from two symbiotic strains of V. fischeri. These genes provide a glimpse into the microhabitat V. fischeri encounters in both free-living seawater and symbiotic host light organ-associated habitats, providing insight into the elements necessary for local adaptation and the evolution of host specificity in this unique mutualism.},
}
@article {pmid17369329,
year = {2007},
author = {Kaeding, AJ and Ast, JC and Pearce, MM and Urbanczyk, H and Kimura, S and Endo, H and Nakamura, M and Dunlap, PV},
title = {Phylogenetic diversity and cosymbiosis in the bioluminescent symbioses of "Photobacterium mandapamensis".},
journal = {Applied and environmental microbiology},
volume = {73},
number = {10},
pages = {3173-3182},
doi = {10.1128/AEM.02212-06},
pmid = {17369329},
issn = {0099-2240},
mesh = {Animals ; Bacterial Proteins/genetics ; *Biodiversity ; DNA, Bacterial/chemistry/genetics ; *Ecosystem ; Fishes/*microbiology ; Luminescence ; Molecular Sequence Data ; Photobacterium/classification/isolation & purification/*physiology ; Phylogeny ; Riboflavin/genetics ; Sequence Analysis, DNA ; Sequence Homology ; *Symbiosis ; },
abstract = {"Photobacterium mandapamensis" (proposed name) and Photobacterium leiognathi are closely related, phenotypically similar marine bacteria that form bioluminescent symbioses with marine animals. Despite their similarity, however, these bacteria can be distinguished phylogenetically by sequence divergence of their luminescence genes, luxCDAB(F)E, by the presence (P. mandapamensis) or the absence (P. leiognathi) of luxF and, as shown here, by the sequence divergence of genes involved in the synthesis of riboflavin, ribBHA. To gain insight into the possibility that P. mandapamensis and P. leiognathi are ecologically distinct, we used these phylogenetic criteria to determine the incidence of P. mandapamensis as a bioluminescent symbiont of marine animals. Five fish species, Acropoma japonicum (Perciformes, Acropomatidae), Photopectoralis panayensis and Photopectoralis bindus (Perciformes, Leiognathidae), Siphamia versicolor (Perciformes, Apogonidae), and Gadella jordani (Gadiformes, Moridae), were found to harbor P. mandapamensis in their light organs. Specimens of A. japonicus, P. panayensis, and P. bindus harbored P. mandapamensis and P. leiognathi together as cosymbionts of the same light organ. Regardless of cosymbiosis, P. mandapamensis was the predominant symbiont of A. japonicum, and it was the apparently exclusive symbiont of S. versicolor and G. jordani. In contrast, P. leiognathi was found to be the predominant symbiont of P. panayensis and P. bindus, and it appears to be the exclusive symbiont of other leiognathid fishes and a loliginid squid. A phylogenetic test for cospeciation revealed no evidence of codivergence between P. mandapamensis and its host fishes, indicating that coevolution apparently is not the basis for this bacterium's host preferences. These results, which are the first report of bacterial cosymbiosis in fish light organs and the first demonstration that P. leiognathi is not the exclusive light organ symbiont of leiognathid fishes, demonstrate that the host species ranges of P. mandapamensis and P. leiognathi are substantially distinct. The host range difference underscores possible differences in the environmental distributions and physiologies of these two bacterial species.},
}
@article {pmid17345129,
year = {2007},
author = {Jones, BW and Maruyama, A and Ouverney, CC and Nishiguchi, MK},
title = {Spatial and temporal distribution of the vibrionaceae in coastal waters of Hawaii, Australia, and France.},
journal = {Microbial ecology},
volume = {54},
number = {2},
pages = {314-323},
doi = {10.1007/s00248-006-9204-z},
pmid = {17345129},
issn = {0095-3628},
support = {GM48998/GM/NIGMS NIH HHS/United States ; GM61222-01/GM/NIGMS NIH HHS/United States ; SO6 GM08136-26/GM/NIGMS NIH HHS/United States ; },
mesh = {Animals ; Australia ; Decapodiformes/microbiology ; France ; Hawaii ; In Situ Hybridization, Fluorescence ; Seasons ; Seawater/chemistry/*microbiology ; Temperature ; Vibrionaceae/*isolation & purification ; },
abstract = {Relatively little is known about large-scale spatial and temporal fluctuations in bacterioplankton, especially within the bacterial families. In general, however, a number of abiotic factors (namely, nutrients and temperature) appear to influence distribution. Community dynamics within the Vibrionaceae are of particular interest to biologists because this family contains a number of important pathogenic, commensal, and mutualist species. Of special interest to this study is the mutualism between sepiolid squids and Vibrio fischeri and Vibrio logei, where host squids seed surrounding waters daily with their bacterial partners. This study seeks to examine the spatial and temporal distribution of the Vibrionaceae with respect to V. fischeri and V. logei in Hawaii, southeastern Australia, and southern France sampling sites. In particular, we examine how the presence of sepiolid squid hosts influences community population structure within the Vibrionaceae. We found that abiotic (temperature) and biotic (host distribution) factors both influence population dynamics. In Hawaii, three sites within squid host habitat contained communities of Vibrionaceae with higher proportions of V. fischeri. In Australia, V. fischeri numbers at host collection sites were greater than other populations; however, there were no spatial or temporal patterns seen at other sample sites. In France, host presence did not appear to influence Vibrio communities, although sampled populations were significantly greater in the winter than summer sampling periods. Results of this study demonstrate the importance of understanding how both abiotic and biotic factors interact to influence bacterial community structure within the Vibrionaceae.},
}
@article {pmid17301329,
year = {2007},
author = {Koropatnick, TA and Kimbell, JR and McFall-Ngai, MJ},
title = {Responses of host hemocytes during the initiation of the squid-Vibrio symbiosis.},
journal = {The Biological bulletin},
volume = {212},
number = {1},
pages = {29-39},
doi = {10.2307/25066578},
pmid = {17301329},
issn = {0006-3185},
support = {AI 50661/AI/NIAID NIH HHS/United States ; RR 12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*physiology ; Animals ; Apoptosis ; Decapodiformes/growth & development/metabolism/*microbiology ; Gene Expression Regulation ; Hemocytes/metabolism/microbiology/*physiology ; Morphogenesis ; Proteasome Endopeptidase Complex/genetics/metabolism ; Protein Subunits/genetics/metabolism ; Symbiosis/genetics/*physiology ; },
abstract = {Within hours after colonization of the light organ of the squid Euprymna scolopes by its bacterial symbiont Vibrio fischeri, the symbiont triggers morphogenesis of the light organ. This process involves the induction of apoptosis in the cells of two superficial ciliated epithelial fields and the gradual regression of these surface structures over a 96-h period. In this study, microscopic examination of various squid tissues revealed that host hemocytes specifically migrate into the epithelial fields on the surface of the light organ, a process that begins before any other indication of symbiont-induced morphogenesis. Experimental manipulations of symbiont-signal delivery revealed that hemocyte infiltration alone is not sufficient to induce regression, and high numbers of hemocytes are not necessary for the induction of apoptosis or the initiation of regression. However, studies with mutant strains of V. fischeri that show a defect in the induction of hemocyte infiltration provided evidence that high numbers of hemocytes facilitate the regression of the epithelial fields. In addition, a change in hemocyte gene expression, as indicated by the up-regulation of the C8 subunit of the proteasome, correlates with the induction of light organ morphogenesis, suggesting that bacteria-induced molecular changes in the hemocytes are required for the participation of these host cells in the regression process.},
}
@article {pmid17237039,
year = {2007},
author = {Delcher, AL and Bratke, KA and Powers, EC and Salzberg, SL},
title = {Identifying bacterial genes and endosymbiont DNA with Glimmer.},
journal = {Bioinformatics (Oxford, England)},
volume = {23},
number = {6},
pages = {673-679},
doi = {10.1093/bioinformatics/btm009},
pmid = {17237039},
issn = {1367-4811},
support = {R01 GM083873/GM/NIGMS NIH HHS/United States ; R01-LM006845/LM/NLM NIH HHS/United States ; R01 LM006845-08/LM/NLM NIH HHS/United States ; R01 LM007938/LM/NLM NIH HHS/United States ; R01-LM007938/LM/NLM NIH HHS/United States ; R01 LM006845/LM/NLM NIH HHS/United States ; R01 LM007938-04/LM/NLM NIH HHS/United States ; HHSN266200400038C//PHS HHS/United States ; },
mesh = {Algorithms ; Animals ; Artifacts ; Chromosome Mapping/*methods ; DNA, Bacterial/*genetics ; Decapodiformes/*genetics/microbiology ; Genome, Bacterial/*genetics ; Prochloron/*genetics ; Reproducibility of Results ; Sensitivity and Specificity ; Sequence Analysis, DNA/methods ; *Software ; Symbiosis/*genetics ; },
abstract = {MOTIVATION: The Glimmer gene-finding software has been successfully used for finding genes in bacteria, archaea and viruses representing hundreds of species. We describe several major changes to the Glimmer system, including improved methods for identifying both coding regions and start codons. We also describe a new module of Glimmer that can distinguish host and endosymbiont DNA. This module was developed in response to the discovery that eukaryotic genome sequencing projects sometimes inadvertently capture the DNA of intracellular bacteria living in the host.

RESULTS: The new methods dramatically reduce the rate of false-positive predictions, while maintaining Glimmer's 99% sensitivity rate at detecting genes in most species, and they find substantially more correct start sites, as measured by comparisons to known and well-curated genes. We show that our interpolated Markov model (IMM) DNA discriminator correctly separated 99% of the sequences in a recent genome project that produced a mixture of sequences from the bacterium Prochloron didemni and its sea squirt host, Lissoclinum patella.

RESULTS: We generated eleven cDNA libraries from the light organ of E. scolopes at developmentally significant time points with and without colonization by V. fischeri. Single pass 3' sequencing efforts generated 42,564 expressed sequence tags (ESTs) of which 35,421 passed our quality criteria and were then clustered via the UIcluster program into 13,962 nonredundant sequences. The cDNA clones representing these nonredundant sequences were sequenced from the 5' end of the vector and 58% of these resulting sequences overlapped significantly with the associated 3' sequence to generate 8,067 contigs with an average sequence length of 1,065 bp. All sequences were annotated with BLASTX (E-value < -03) and Gene Ontology (GO).

CONCLUSION: Both the number of ESTs generated from each library and GO categorizations are reflective of the activity state of the light organ during these early stages of symbiosis. Future analyses of the sequences identified in these libraries promise to provide valuable information not only about pathways involved in colonization and early development of the squid light organ, but also about pathways conserved in response to bacterial colonization across the animal kingdom.},
}
@article {pmid16623398,
year = {2006},
author = {Geszvain, K and Visick, KL},
title = {Roles of bacterial regulators in the symbiosis between Vibrio fischeri and Euprymna scolopes.},
journal = {Progress in molecular and subcellular biology},
volume = {41},
number = {},
pages = {277-290},
pmid = {16623398},
issn = {0079-6484},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Animals ; Decapodiformes/*microbiology ; Gene Expression Regulation, Bacterial ; *Signal Transduction ; *Symbiosis ; },
}
@article {pmid16501931,
year = {2006},
author = {Vázquez, JA and Docasal, SF and Mirón, J and González, MP and Murado, MA},
title = {Proteases production by two Vibrio species on residuals marine media.},
journal = {Journal of industrial microbiology & biotechnology},
volume = {33},
number = {8},
pages = {661-668},
doi = {10.1007/s10295-006-0096-1},
pmid = {16501931},
issn = {1367-5435},
mesh = {Alkalies ; Animals ; Culture Media ; Fishes ; Industrial Microbiology/*methods ; Kinetics ; Models, Biological ; Peptide Hydrolases/*biosynthesis ; *Peptones/isolation & purification ; Species Specificity ; Vibrio/growth & development/*metabolism ; Viscera/chemistry ; },
abstract = {A comparative study was carried out on the growth and production of alkaline proteases by two Vibrio species using different marine peptones from fish viscera residues. The bacteria tested, Vibrio anguillarum and Vibrio splendidus, are producers of high levels of proteolytic enzymes which act as factors of virulence in fish cultures, causing high mortality rates. The kinetic assays and subsequent comparison with the parameters obtained from the adjustment to various mathematical models, highlighted the potential interest of the media formulated, for their possible production on an industrial scale, particularly the production of proteases by V. anguillarum growing in rainbow trout and squid peptones.},
}
@article {pmid16429442,
year = {2006},
author = {Sycuro, LK and Ruby, EG and McFall-Ngai, M},
title = {Confocal microscopy of the light organ crypts in juvenile Euprymna scolopes reveals their morphological complexity and dynamic function in symbiosis.},
journal = {Journal of morphology},
volume = {267},
number = {5},
pages = {555-568},
doi = {10.1002/jmor.10422},
pmid = {16429442},
issn = {0362-2525},
support = {AI-50661/AI/NIAID NIH HHS/United States ; RR-12292/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Animals ; Decapodiformes/anatomy & histology/*cytology/*microbiology ; Digestive System/anatomy & histology/*cytology/*microbiology ; Epithelial Cells/cytology ; Microscopy, Confocal ; *Symbiosis ; },
abstract = {In the hours to days following hatching, the Hawaiian bobtail squid, Euprymna scolopes, obtains its light-emitting symbiont, Vibrio fischeri, from the surrounding environment and propagates the bacteria in the epithelial crypts of a specialized light organ. Three-dimensional analyses using confocal microscopy revealed that each of the three crypts on either side of the juvenile light organ is composed of four morphological regions. Progressing from the lateral pore to the medial blind end of each crypt, the regions consist of 1) a duct, 2) an antechamber, 3) a bottleneck, and 4) a deep region. Only the deep region houses a persistent bacterial population, whereas the duct, antechamber, and bottleneck serve as conduits through which the bacteria enter during initial colonization and exit during diel venting, a behavior in which approximately 90% of the symbionts are expelled each dawn. Our data suggest that, like the duct, the antechamber and bottleneck may function to promote and maintain the specificity of the symbiosis. Pronounced structural and functional differences among the deep regions of the three crypts, along with previously reported characterizations of embryogenesis, suggest a continued developmental progression in the first few days after hatching. Taken together, the results of this study reveal a high degree of complexity in the morphology of the crypts, as well as in the extent to which the three crypts and their constituent regions differ in function during the early stages of the symbiosis.},
}
@article {pmid16391121,
year = {2006},
author = {Dunn, AK and Millikan, DS and Adin, DM and Bose, JL and Stabb, EV},
title = {New rfp- and pES213-derived tools for analyzing symbiotic Vibrio fischeri reveal patterns of infection and lux expression in situ.},
journal = {Applied and environmental microbiology},
volume = {72},
number = {1},
pages = {802-810},
doi = {10.1128/AEM.72.1.802-810.2006},
pmid = {16391121},
issn = {0099-2240},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; R01 AI 50661/AI/NIAID NIH HHS/United States ; },
mesh = {Acyltransferases/genetics/metabolism ; Aliivibrio fischeri/genetics/*growth & development/metabolism ; Animal Structures/microbiology ; Animals ; Bacterial Proteins/genetics/metabolism ; Base Sequence ; Decapodiformes/*microbiology ; *Genetic Vectors ; Green Fluorescent Proteins/chemistry/genetics/metabolism ; Light ; Luminescent Proteins/chemistry/genetics/*metabolism ; Molecular Sequence Data ; Oxidoreductases/genetics/metabolism ; *Plasmids/genetics ; *Symbiosis ; },
abstract = {Genetically altered or tagged Vibrio fischeri strains can be observed in association with their mutualistic host Euprymna scolopes, providing powerful experimental approaches for studying this symbiosis. Two limitations to such in situ analyses are the lack of suitably stable plasmids and the need for a fluorescent tag that can be used in tandem with green fluorescent protein (GFP). Vectors previously used in V. fischeri contain the p15A replication origin; however, we found that this replicon is not stable during growth in the host and is retained by fewer than 20% of symbionts within a day after infection. In contrast, derivatives of V. fischeri plasmid pES213 were retained by approximately 99% of symbionts even 3 days after infection. We therefore constructed pES213-derived shuttle vectors with a variety of selectable and visual markers. To include a visual tag that can be used in conjunction with GFP, we compared seven variants of the DsRed2 red fluorescent protein (RFP): mRFP1, tdimer2(12), DsRed.T3, DsRed.T4, DsRed.M1, DsRed.T3_S4T, and DsRed.T3(DNT). The last variant was brightest, displaying >20-fold more fluorescence than DsRed2 in V. fischeri. RFP expression did not detectably affect the fitness of V. fischeri, and cells were readily visualized in combination with GFP-expressing cells in mixed infections. Interestingly, even when inocula were dense enough that most E. scolopes hatchlings were infected by two strains, there was little mixing of the strains in the light organ crypts. We also used constitutive RFP in combination with the luxICDABEG promoter driving expression of GFP to visualize the spatial and temporal induction of this bioluminescence operon during symbiotic infection. Our results demonstrate the utility of pES213-based vectors and RFP for in situ experimental approaches in studies of the V. fischeri-E. scolopes symbiosis.},
}
@article {pmid16349524,
year = {1998},
author = {Ruby, EG and Lee, KH},
title = {The Vibrio fischeri-Euprymna scolopes Light Organ Association: Current Ecological Paradigms.},
journal = {Applied and environmental microbiology},
volume = {64},
number = {3},
pages = {805-812},
pmid = {16349524},
issn = {0099-2240},
}
@article {pmid16305176,
year = {2005},
author = {Maruyama, Y and Kimura, B and Fujii, T and Tokunaga, Y and Matsubayashi, M and Aikawa, Y},
title = {[Growth inhibition of Vibrio parahaemolyticus in seafood by tabletop dry ice cooler].},
journal = {Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan},
volume = {46},
number = {5},
pages = {213-217},
pmid = {16305176},
issn = {0015-6426},
mesh = {*Dry Ice ; Food Preservation/methods ; Seafood/*microbiology ; Vibrio parahaemolyticus/*growth & development ; },
abstract = {Tabletop dry ice coolers (three types; dome model, cap model and tripod model), which are used in kitchens and hotel banquet halls to refrigerate fresh seafood, were investigated to determine whether growth of Vibrio parahaemolyticus was inhibited by their use. On TSA plates containing 1.8% NaCl and fresh seafood (fillets of squid, pink shrimp and yellowtail), V. parahaemolyticus (O3:K6, TDH+) inoculated at 4 to 5 log CFU/sample and left at ambient temperature (25 degrees C) grew by 1.0 to 2.8 orders in 4 hours. In contrast, with tabletop coolers no significant increase in viable count occurred in 3 to 4 hours, confirming that tabletop coolers inhibited the growth of V. parahaemolyticus. The temperature in each tabletop cooler was kept below 10 degrees C for 80 to 135 min, though the CO2 gas concentration in them remained high for only a short time (0 to 75 min). It was presumed that the refrigeration function mainly contributed to growth inhibition. Our results indicate that tabletop dry ice coolers are helpful for prevention of food-borne disease due to V. parahaemolyticus in food-service locations, such as kitchens and banquet halls.},
}
@article {pmid16269728,
year = {2005},
author = {Goodson, MS and Kojadinovic, M and Troll, JV and Scheetz, TE and Casavant, TL and Soares, MB and McFall-Ngai, MJ},
title = {Identifying components of the NF-kappaB pathway in the beneficial Euprymna scolopes-Vibrio fischeri light organ symbiosis.},
journal = {Applied and environmental microbiology},
volume = {71},
number = {11},
pages = {6934-6946},
doi = {10.1128/AEM.71.11.6934-6946.2005},
pmid = {16269728},
issn = {0099-2240},
support = {R01 AI050611/AI/NIAID NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; AI 50611/AI/NIAID NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/growth & development/*metabolism ; Amino Acid Sequence ; Animal Structures/growth & development/metabolism/*microbiology ; Animals ; DNA, Complementary/genetics/metabolism ; Decapodiformes/genetics/growth & development/metabolism/*microbiology ; Expressed Sequence Tags/metabolism ; Gene Expression Regulation ; Humans ; *Light ; Molecular Sequence Data ; NF-kappa B/*metabolism ; Organ Specificity ; Signal Transduction ; Species Specificity ; *Symbiosis ; Transcription, Genetic ; },
abstract = {The Toll/NF-kappaB pathway is a common, evolutionarily conserved innate immune pathway that modulates the responses of animal cells to microbe-associated molecular patterns (MAMPs). Because MAMPs have been implicated as critical elements in the signaling of symbiont-induced development, an expressed sequence tag library from the juvenile light organ of Euprymna scolopes was used to identify members of the Toll/NF-kappaB pathway. Full-length transcripts were identified by using 5' and 3' RACE PCR. Seven transcripts critical for MAMP-induced triggering of the Toll/NF-kappaB phosphorylation cascade have been identified, including receptors, signal transducers, and a transcription factor. Further investigations should elucidate the role of the Toll/NF-kappaB pathway in the initiation of the beneficial symbiosis between E. scolopes and Vibrio fischeri.},
}
@article {pmid16231859,
year = {2005},
author = {Holden, M and Thomson, N and Bentley, S},
title = {Microbial mariners.},
journal = {Nature reviews. Microbiology},
volume = {3},
number = {10},
pages = {748-749},
doi = {10.1038/nrmicro1262},
pmid = {16231859},
issn = {1740-1526},
mesh = {Adaptation, Physiological ; Aliivibrio fischeri/genetics/*physiology ; Alphaproteobacteria/*genetics ; Animals ; Cold Temperature ; Decapodiformes/microbiology ; Gammaproteobacteria/*genetics/physiology ; Genome, Bacterial ; Seawater/*microbiology ; Symbiosis/physiology ; },
}
@article {pmid16122560,
year = {2005},
author = {Dunn, AK and Martin, MO and Stabb, EV},
title = {Characterization of pES213, a small mobilizable plasmid from Vibrio fischeri.},
journal = {Plasmid},
volume = {54},
number = {2},
pages = {114-134},
doi = {10.1016/j.plasmid.2005.01.003},
pmid = {16122560},
issn = {0147-619X},
support = {R01 AI 50661/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*genetics ; Amino Acid Sequence ; Base Sequence ; Cloning, Molecular ; *Conjugation, Genetic ; DNA Replication ; Gene Dosage ; Molecular Sequence Data ; Mutation ; Plasmids/*genetics ; Rec A Recombinases/genetics ; Replication Origin ; Sequence Analysis ; Symbiosis ; },
abstract = {Most Vibrio fischeri strains isolated from the Euprymna scolopes light organ carry plasmids, often including both a large (>40kb) plasmid, and one or more small (<12kb) plasmids. The large plasmids share homology with pES100, which is the lone plasmid in V. fischeri type strain ES114. pES100 appears to encode a conjugative system similar to that on plasmid R721. The small plasmids lack extensive similarity to pES100, but they almost always occur in cells that also harbor a large plasmid resembling pES100. We found that many or all of these small plasmids share homology with pES213, a plasmid in strain ES213. We determined the 5501-bp pES213 sequence and generated selectable antibiotic resistance encoding pES213 derivatives, which enabled us to examine replication, retention, and transfer in V. fischeri. An 863-bp fragment of pES213 with features characteristic of theta-type replicons conferred replication without requiring any pES213 open reading frame (ORF). We estimated that pES213 derivatives were maintained at 9.4 copies per genome, which corresponds well with a model of random plasmid segregation to daughter cells and the approximately 10(-4) per generation frequency of plasmid loss. pES213 derivatives mobilized between V. fischeri strains at frequencies up to approximately 10(-4) in culture and in the host, apparently by employing the pES100 conjugative apparatus. pES213 carries two homologs of the putative pES100 origin of transfer (oriT), and V. fischeri strains lacking the pES100 conjugative relaxase, including a relaxase mutant, failed to serve as donors for transmission of pES213 derivatives. In other systems, genes directing conjugative transfer can function in trans to oriT, so it was noteworthy that ORFs adjacent to oriT, VFB51 in pES100 and traYZ in pES213, enhanced transfer 100- to 1000-fold when provided in cis. We also identified and disrupted the V. fischeri recA gene. RecA was not required for stable pES213 replication but surprisingly was required in donors for efficient transfer of pES213 derivatives. These studies provide an explanation for the prevalence and co-occurrence of pES100- and pES213-type plasmids, illuminate novel elements of pES213 mobilization, and provide the foundation for new genetic tools in V. fischeri.},
}
@article {pmid16102015,
year = {2005},
author = {Yip, ES and Grublesky, BT and Hussa, EA and Visick, KL},
title = {A novel, conserved cluster of genes promotes symbiotic colonization and sigma-dependent biofilm formation by Vibrio fischeri.},
journal = {Molecular microbiology},
volume = {57},
number = {5},
pages = {1485-1498},
doi = {10.1111/j.1365-2958.2005.04784.x},
pmid = {16102015},
issn = {0950-382X},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*genetics/*physiology ; Bacterial Proteins/genetics ; Base Sequence ; Biofilms/*growth & development ; Gene Expression Regulation, Bacterial ; Genes, Bacterial/*physiology ; Molecular Sequence Data ; Multigene Family ; Sigma Factor/genetics/*metabolism ; Symbiosis/genetics ; Transcription, Genetic ; },
abstract = {Vibrio fischeri is the exclusive symbiont residing in the light organ of the squid Euprymna scolopes. To understand the genetic requirements for this association, we searched a library of V. fischeri transposon insertion mutants for those that failed to colonize E. scolopes. We identified four mutants that exhibited severe defects in initiating colonization. Sequence analysis revealed that the strains contained insertions in four different members of a cluster of 21 genes oriented in the same direction. The predicted gene products are similar to proteins involved in capsule, exopolysaccharide or lipopolysaccharide biosynthesis, including six putative glycosyltransferases. We constructed mutations in five additional genes and found that they also were required for symbiosis. Therefore, we have termed this region syp, for symbiosis polysaccharide. Homologous clusters also exist in Vibrio parahaemolyticus and Vibrio vulnificus, and thus these genes may represent a common mechanism for promoting bacteria-host interactions. Using lacZ reporter fusions, we observed that transcription of the syp genes did not occur under standard laboratory conditions, but could be induced by multicopy expression of sypG, which encodes a response regulator with a predicted sigma54 interaction domain. This induction depended on sigma54, as a mutation in rpoN abolished syp transcription. Primer extension analysis supported the use of putative sigma54 binding sites upstream of sypA, sypI and sypM as promoters. Finally, we found that multicopy expression of sypG resulted in robust biofilm formation. This work thus reveals a novel group of genes that V. fischeri controls through a sigma54-dependent response regulator and uses to promote symbiotic colonization.},
}
@article {pmid16091889,
year = {2005},
author = {Morita, N and Ichise, N and Yumoto, I and Yano, Y and Ohgiya, S and Okuyama, H},
title = {Cultivation of microorganisms in the cultural medium made from squid internal organs and accumulation of polyunsaturated fatty acids in the cells.},
journal = {Biotechnology letters},
volume = {27},
number = {13},
pages = {933-941},
doi = {10.1007/s10529-005-7187-3},
pmid = {16091889},
issn = {0141-5492},
mesh = {Animals ; Bacteria/drug effects/growth & development/*metabolism ; Culture Media/chemistry/*pharmacology ; Decapodiformes/*chemistry ; Docosahexaenoic Acids/metabolism ; Eicosapentaenoic Acid/metabolism ; Escherichia coli/drug effects/growth & development/metabolism ; Fatty Acids, Unsaturated/chemistry/metabolism/pharmacology ; Lipid Metabolism ; Lipids/chemistry ; Moritella/drug effects/growth & development/metabolism ; Shewanella putrefaciens/drug effects/growth & development/metabolism ; Species Specificity ; Vibrio/drug effects/growth & development/metabolism ; },
abstract = {The disposal and more efficient utilization of marine wastes is becoming increasingly serious. A culture media for microorganisms has been prepared from squid internal organs that are rich in polyunsaturated fatty acids (PUFAs). Both freshwater and marine bacteria grew well in this medium and some bacteria accumulated PUFAs in their lipids, suggesting uptake of exogenous PUFAs. Higher PUFA accumulations were observed in Escherichia coli mutant cells defective either in unsaturated fatty acid biosynthesis or fatty acid degradation, or both, compared to those without these mutations. Therefore, PUFA accumulation in cells can be improved by genetic modification of fatty acid metabolism in the bacteria. Squid internal organs would be a good source of medium, not only for marine bacteria but also for freshwater bacteria, and that this process may be advantageous to make efficient use of the fishery wastes and to produce PUFA-containing microbial cells and lipids.},
}
@article {pmid15901683,
year = {2005},
author = {Lupp, C and Ruby, EG},
title = {Vibrio fischeri uses two quorum-sensing systems for the regulation of early and late colonization factors.},
journal = {Journal of bacteriology},
volume = {187},
number = {11},
pages = {3620-3629},
doi = {10.1128/JB.187.11.3620-3629.2005},
pmid = {15901683},
issn = {0021-9193},
support = {R01 RR012294/RR/NCRR NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/genetics/*growth & development/*physiology ; Animals ; Decapodiformes/*microbiology ; Flagella/physiology ; Gene Expression Regulation, Bacterial ; Luminescent Measurements ; Luminescent Proteins/genetics ; Mutation ; Oligonucleotide Array Sequence Analysis ; Phenotype ; Signal Transduction/*physiology ; Symbiosis/*physiology ; },
abstract = {Vibrio fischeri possesses two quorum-sensing systems, ain and lux, using acyl homoserine lactones as signaling molecules. We have demonstrated previously that the ain system activates luminescence gene expression at lower cell densities than those required for lux system activation and that both systems are essential for persistent colonization of the squid host, Euprymna scolopes. Here, we asked whether the relative contributions of the two systems are also important at different colonization stages. Inactivation of ain, but not lux, quorum-sensing genes delayed initiation of the symbiotic relationship. In addition, our data suggest that lux quorum sensing is not fully active in the early stages of colonization, implying that this system is not required until later in the symbiosis. The V. fischeri luxI mutant does not express detectable light levels in symbiosis yet initiates colonization as well as the wild type, suggesting that ain quorum sensing regulates colonization factors other than luminescence. We used a recently developed V. fischeri microarray to identify genes that are controlled by ain quorum sensing and could be responsible for the initiation defect. We found 30 differentially regulated genes, including the repression of a number of motility genes. Consistent with these data, ain quorum-sensing mutants displayed an altered motility behavior in vitro. Taken together, these data suggest that the sequential activation of these two quorum-sensing systems with increasing cell density allows the specific regulation of early colonization factors (e.g., motility) by ain quorum sensing, whereas late colonization factors (e.g., luminescence) are preferentially regulated by lux quorum sensing.},
}
@article {pmid15901681,
year = {2005},
author = {Visick, KL},
title = {Layers of signaling in a bacterium-host association.},
journal = {Journal of bacteriology},
volume = {187},
number = {11},
pages = {3603-3606},
doi = {10.1128/JB.187.11.3603-3606.2005},
pmid = {15901681},
issn = {0021-9193},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*physiology ; Animals ; Decapodiformes/*microbiology ; Signal Transduction/*physiology ; *Symbiosis ; },
}
@article {pmid15743954,
year = {2005},
author = {O'Shea, TM and Deloney-Marino, CR and Shibata, S and Aizawa, S and Wolfe, AJ and Visick, KL},
title = {Magnesium promotes flagellation of Vibrio fischeri.},
journal = {Journal of bacteriology},
volume = {187},
number = {6},
pages = {2058-2065},
doi = {10.1128/JB.187.6.2058-2065.2005},
pmid = {15743954},
issn = {0021-9193},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {Agar ; Aliivibrio fischeri/*physiology/*ultrastructure ; Animals ; Calcium/pharmacology/physiology ; Cations, Divalent/metabolism/pharmacology ; Culture Media/pharmacology ; Decapodiformes/*microbiology ; Flagella/*physiology ; Locomotion/drug effects/physiology ; Magnesium/pharmacology/*physiology ; Symbiosis ; },
abstract = {The bacterium Vibrio fischeri requires bacterial motility to initiate colonization of the Hawaiian squid Euprymna scolopes. Once colonized, however, the bacterial population becomes largely unflagellated. To understand environmental influences on V. fischeri motility, we investigated migration of this organism in tryptone-based soft agar media supplemented with different salts. We found that optimal migration required divalent cations and, in particular, Mg2+. At concentrations naturally present in seawater, Mg2+ improved migration without altering the growth rate of the cells. Transmission electron microscopy and Western blot experiments suggested that Mg2+ addition enhanced flagellation, at least in part through an effect on the steady-state levels of flagellin protein.},
}
@article {pmid15703294,
year = {2005},
author = {Ruby, EG and Urbanowski, M and Campbell, J and Dunn, A and Faini, M and Gunsalus, R and Lostroh, P and Lupp, C and McCann, J and Millikan, D and Schaefer, A and Stabb, E and Stevens, A and Visick, K and Whistler, C and Greenberg, EP},
title = {Complete genome sequence of Vibrio fischeri: a symbiotic bacterium with pathogenic congeners.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {102},
number = {8},
pages = {3004-3009},
doi = {10.1073/pnas.0409900102},
pmid = {15703294},
issn = {0027-8424},
mesh = {Aliivibrio fischeri/*genetics/pathogenicity ; Bacterial Toxins/genetics ; Base Composition ; Base Sequence ; Fimbriae, Bacterial/genetics ; *Genome, Bacterial ; Multigene Family ; Open Reading Frames ; Plasmids ; *Symbiosis ; },
abstract = {Vibrio fischeri belongs to the Vibrionaceae, a large family of marine gamma-proteobacteria that includes several dozen species known to engage in a diversity of beneficial or pathogenic interactions with animal tissue. Among the small number of pathogenic Vibrio species that cause human diseases are Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus, the only members of the Vibrionaceae that have had their genome sequences reported. Nonpathogenic members of the genus Vibrio, including a number of beneficial symbionts, make up the majority of the Vibrionaceae, but none of these species has been similarly examined. Here we report the genome sequence of V. fischeri ES114, which enters into a mutualistic symbiosis in the light organ of the bobtail squid, Euprymna scolopes. Analysis of this sequence has revealed surprising parallels with V. cholerae and other pathogens.},
}
@article {pmid15609878,
year = {2004},
author = {Trilles, JP and Oktener, A},
title = {Livoneca sinuata (Crustacea; Isopoda; Cymothoidae) on Loligo vulgaris from Turkey, and unusual cymothoid associations.},
journal = {Diseases of aquatic organisms},
volume = {61},
number = {3},
pages = {235-240},
doi = {10.3354/dao061235},
pmid = {15609878},
issn = {0177-5103},
mesh = {Animals ; Decapodiformes/*parasitology ; Female ; Host-Parasite Interactions ; Isopoda/*physiology ; Male ; Mediterranean Sea ; *Symbiosis ; Turkey ; },
abstract = {In this paper, an unusual association of Livoneca sinuata (Crustacea; Isopoda; Cymothoidae) with the cephalopod Loligo vulgaris is reported for the first time from the Aegean sea coasts of Turkey. Moreover, a review of all the cases of unusual associations involving cymothoids is performed.},
}
@article {pmid15539604,
year = {2004},
author = {Koropatnick, TA and Engle, JT and Apicella, MA and Stabb, EV and Goldman, WE and McFall-Ngai, MJ},
title = {Microbial factor-mediated development in a host-bacterial mutualism.},
journal = {Science (New York, N.Y.)},
volume = {306},
number = {5699},
pages = {1186-1188},
doi = {10.1126/science.1102218},
pmid = {15539604},
issn = {1095-9203},
support = {NCRR12294/RR/NCRR NIH HHS/United States ; R01-AI50661/AI/NIAID NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/growth & development/metabolism/*physiology ; Animals ; Apoptosis ; Bacterial Toxins/metabolism/pharmacology ; Chromatography, High Pressure Liquid ; Cytotoxins/*metabolism/pharmacology ; Decapodiformes/cytology/*growth & development/*microbiology ; Epithelial Cells/cytology/physiology ; Epithelium/microbiology/physiology ; Hemocytes/physiology ; Lipopolysaccharides/*metabolism ; Morphogenesis ; Peptidoglycan/chemistry/*metabolism ; *Symbiosis ; },
abstract = {Tracheal cytotoxin (TCT), a fragment of the bacterial surface molecule peptidoglycan (PGN), is the factor responsible for the extensive tissue damage characteristic of whooping cough and gonorrhea infections. Here, we report that Vibrio fischeri also releases TCT, which acts in synergy with lipopolysaccharide (LPS) to trigger tissue development in its mutualistic symbiosis with the squid Euprymna scolopes. As components of PGN and LPS have commonly been linked with pathogenesis in animals, these findings demonstrate that host interpretation of these bacterial signal molecules is context dependent. Therefore, such differences in interpretation can lead to either inflammation and disease or to the establishment of a mutually beneficial animal-microbe association.},
}
@article {pmid15527494,
year = {2004},
author = {Davidson, SK and Koropatnick, TA and Kossmehl, R and Sycuro, L and McFall-Ngai, MJ},
title = {NO means 'yes' in the squid-vibrio symbiosis: nitric oxide (NO) during the initial stages of a beneficial association.},
journal = {Cellular microbiology},
volume = {6},
number = {12},
pages = {1139-1151},
doi = {10.1111/j.1462-5822.2004.00429.x},
pmid = {15527494},
issn = {1462-5814},
support = {AI50611/AI/NIAID NIH HHS/United States ; GM201177/GM/NIGMS NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aliivibrio fischeri/*growth & development ; Animals ; Decapodiformes/*microbiology ; Light ; Nitric Oxide/*metabolism ; Nitric Oxide Synthase/metabolism ; Organ Specificity ; *Symbiosis ; },
abstract = {During colonization of the Euprymna scolopes light organ, symbiotic Vibrio fischeri cells aggregate in mucus secreted by a superficial ciliated host epithelium near the sites of eventual inoculation. Once aggregated, symbiont cells migrate through ducts into epithelium-lined crypts, where they form a persistent association with the host. In this study, we provide evidence that nitric oxide synthase (NOS) and its product nitric oxide (NO) are active during the colonization of host tissues by V. fischeri. NADPH-diaphorase staining and immunocytochemistry detected NOS, and the fluorochrome diaminofluorescein (DAF) detected its product NO in high concentrations in the epithelia of the superficial ciliated fields, ducts, and crypt antechambers. In addition, both NOS and NO were detected in vesicles within the secreted mucus where the symbionts aggregate. In the presence of NO scavengers, cells of a non-symbiotic Vibrio species formed unusually large aggregates outside of the light organ, but these bacteria did not colonize host tissues. In contrast, V. fischeri effectively colonized the crypts and irreversibly attenuated the NOS and NO signals in the ducts and crypt antechambers. These data provide evidence that NO production, a defense response of animal cells to bacterial pathogens, plays a role in the interactions between a host and its beneficial bacterial partner during the initiation of symbiotic colonization.},
}
@article {pmid15376274,
year = {2004},
author = {Furuya, H and Ota, M and Kimura, R and Tsuneki, K},
title = {Renal organs of cephalopods: a habitat for dicyemids and chromidinids.},
journal = {Journal of morphology},
volume = {262},
number = {2},
pages = {629-643},
doi = {10.1002/jmor.10265},
pmid = {15376274},
issn = {0362-2525},
mesh = {Animals ; Decapodiformes/anatomy & histology/parasitology/physiology ; *Ecosystem ; Female ; Invertebrates/embryology/*growth & development ; Kidney/*parasitology ; Male ; Mollusca/*anatomy & histology/*parasitology/physiology ; Octopodiformes/anatomy & histology/parasitology/physiology ; Symbiosis ; },
abstract = {The renal organs of 32 species of cephalopods (renal appendage of all cephalopods, and renal and pancreatic appendages in decapods) were examined for parasite fauna and for histological comparison. Two phylogenetically distant organisms, dicyemid mesozoans and chromidinid ciliates, were found in 20 cephalopod species. Most benthic cephalopods (octopus and cuttlefish) were infected with dicyemids. Two pelagic cephalopod species, Sepioteuthis lessoniana and Todarodes pacificus, also harbored dicyemids. Chromidinid ciliates were found only in decapods (squid and cuttlefish). One dicyemid species was found in branchial heart appendages of Rossia pacifica. Dicyemids and chromidinids occasionally occurred simultaneously in Euprymna morsei, Sepia kobiensis, S. peterseni, and T. pacificus. The small-sized cephalopod species, Idiosepius paradoxus and Octopus parvus, harbored no parasites. Comparative histology revealed that the external surface of renal organs varies morphologically in various cephalopod species. The small-sized cephalopod species have a simple external surface. In contrast, the medium- to large-sized cephalopod species have a complex external surface. In the medium- to large-sized cephalopod species, their juveniles have a simple external surface of the renal organs. The external surface subsequently becomes complicated as they grow. Dicyemids and chromidinids attach their heads to epithelia or insert their heads into folds of renal appendages, pancreatic appendages, and branchial heart appendages. The rugged and convoluted external surface provides a foothold for dicyemids and chromidinids with a conical head. They apparently do not harm these tissues of their host cephalopods.},
}
@article {pmid15353563,
year = {2004},
author = {Thompson, FL and Iida, T and Swings, J},
title = {Biodiversity of vibrios.},
journal = {Microbiology and molecular biology reviews : MMBR},
volume = {68},
number = {3},
pages = {403-31, table of contents},
doi = {10.1128/MMBR.68.3.403-431.2004},
pmid = {15353563},
issn = {1092-2172},
mesh = {Animals ; Bacterial Typing Techniques ; Bacteriology/history ; *Biodiversity ; Cholera/history ; History, 19th Century ; History, 20th Century ; Humans ; Phylogeny ; Vibrio/*classification/genetics/*growth & development/pathogenicity ; Vibrio Infections/*microbiology ; *Water Microbiology ; },
abstract = {Vibrios are ubiquitous and abundant in the aquatic environment. A high abundance of vibrios is also detected in tissues and/or organs of various marine algae and animals, e.g., abalones, bivalves, corals, fish, shrimp, sponges, squid, and zooplankton. Vibrios harbour a wealth of diverse genomes as revealed by different genomic techniques including amplified fragment length polymorphism, multilocus sequence typing, repetetive extragenic palindrome PCR, ribotyping, and whole-genome sequencing. The 74 species of this group are distributed among four different families, i.e., Enterovibrionaceae, Photobacteriaceae, Salinivibrionaceae, and Vibrionaceae. Two new genera, i.e., Enterovibrio norvegicus and Grimontia hollisae, and 20 novel species, i.e., Enterovibrio coralii, Photobacterium eurosenbergii, V. brasiliensis, V. chagasii, V. coralliillyticus, V. crassostreae, V. fortis, V. gallicus, V. hepatarius, V. hispanicus, V. kanaloaei, V. neonatus, V. neptunius, V. pomeroyi, V. pacinii, V. rotiferianus, V. superstes, V. tasmaniensis, V. ezurae, and V. xuii, have been described in the last few years. Comparative genome analyses have already revealed a variety of genomic events, including mutations, chromosomal rearrangements, loss of genes by decay or deletion, and gene acquisitions through duplication or horizontal transfer (e.g., in the acquisition of bacteriophages, pathogenicity islands, and super-integrons), that are probably important driving forces in the evolution and speciation of vibrios. Whole-genome sequencing and comparative genomics through the application of, e.g., microarrays will facilitate the investigation of the gene repertoire at the species level. Based on such new genomic information, the taxonomy and the species concept for vibrios will be reviewed in the next years.},
}
@article {pmid15270503,
year = {2004},
author = {Elhadi, N and Radu, S and Chen, CH and Nishibuchi, M},
title = {Prevalence of potentially pathogenic Vibrio species in the seafood marketed in Malaysia.},
journal = {Journal of food protection},
volume = {67},
number = {7},
pages = {1469-1475},
pmid = {15270503},
issn = {0362-028X},
mesh = {Animals ; Colony Count, Microbial ; *Consumer Product Safety ; Food Contamination/analysis ; Food Microbiology ; Humans ; Malaysia ; Prevalence ; Seafood/*microbiology ; Seasons ; Shellfish/*microbiology ; Vibrio/classification/*isolation & purification/pathogenicity ; },
abstract = {Seafood samples obtained in seafood markets and supermarkets at 11 sites selected from four states in Malaysia were examined for the presence of nine potentially pathogenic species from the genus Vibrio between July 1998 and June 1999. We examined 768 sample sets that included shrimp, squid, crab, cockles, and mussels. We extensively examined shrimp samples from Selangor State to determine seasonal variation of Vibrio populations. Eight potentially pathogenic Vibrio species were detected, with overall incidence in the samples at 4.6% for V. cholerae, 4.7% for V. parahaemolyticus, 6.0% for V. vulnificus, 11% for V. alginolyticus, 9.9% for V. metschnikovii, 1.3% for V. mimicus, 13% for V. damsela, 7.6% for V. fluvialis, and 52% for a combined population of all of the above. As many as eight Vibrio species were detected in shrimp and only four in squid and peel mussels. The overall percent incidence of any of the eight vibrios was highest (82%) in cockles (Anadara granosa) among the seafoods examined and was highest (100%) in Kuching, Sarawak State, and lowest (25%) in Penang, Pulau Penang State, among the sampling sites. Of 97 strains of V. cholerae isolated, one strain belonged to the O1 serotype and 14 to the O139 serotype. The results indicate that the various seafood markets in Malaysia are contaminated with potentially pathogenic Vibrio species regardless of the season and suggest that there is a need for adequate consumer protection measures.},
}
@article {pmid15263898,
year = {2004},
author = {Nyholm, SV and McFall-Ngai, MJ},
title = {The winnowing: establishing the squid-vibrio symbiosis.},
journal = {Nature reviews. Microbiology},
volume = {2},
number = {8},
pages = {632-642},
doi = {10.1038/nrmicro957},
pmid = {15263898},
issn = {1740-1526},
mesh = {Animals ; Bacteria/growth & development ; Decapodiformes/*microbiology ; Symbiosis/*physiology ; Vibrio/*growth & development ; },
}
@article {pmid15232949,
year = {2004},
author = {Sachs, JL and Mueller, UG and Wilcox, TP and Bull, JJ},
title = {The evolution of cooperation.},
journal = {The Quarterly review of biology},
volume = {79},
number = {2},
pages = {135-160},
pmid = {15232949},
issn = {0033-5770},
support = {57756//PHS HHS/United States ; },
mesh = {Algorithms ; Animals ; *Biological Evolution ; Computational Biology ; *Cooperative Behavior ; Humans ; Models, Biological ; Selection, Genetic ; *Sociobiology ; Symbiosis ; },
abstract = {Darwin recognized that natural selection could not favor a trait in one species solely for the benefit of another species. The modern, selfish-gene view of the world suggests that cooperation between individuals, whether of the same species or different species, should be especially vulnerable to the evolution of noncooperators. Yet, cooperation is prevalent in nature both within and between species. What special circumstances or mechanisms thus favor cooperation? Currently, evolutionary biology offers a set of disparate explanations, and a general framework for this breadth of models has not emerged. Here, we offer a tripartite structure that links previously disconnected views of cooperation. We distinguish three general models by which cooperation can evolve and be maintained: (i) directed reciprocation--cooperation with individuals who give in return; (ii) shared genes--cooperation with relatives (e.g., kin selection); and (iii) byproduct benefits--cooperation as an incidental consequence of selfish action. Each general model is further subdivided. Several renowned examples of cooperation that have lacked explanation until recently--plant-rhizobium symbioses and bacteria-squid light organs--fit squarely within this framework. Natural systems of cooperation often involve more than one model, and a fruitful direction for future research is to understand how these models interact to maintain cooperation in the long term.},
}
@article {pmid15205434,
year = {2004},
author = {Millikan, DS and Ruby, EG},
title = {Vibrio fischeri flagellin A is essential for normal motility and for symbiotic competence during initial squid light organ colonization.},
journal = {Journal of bacteriology},
volume = {186},
number = {13},
pages = {4315-4325},
doi = {10.1128/JB.186.13.4315-4325.2004},
pmid = {15205434},
issn = {0021-9193},
support = {R01 RR012294/RR/NCRR NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Chromosome Mapping ; Decapodiformes/*microbiology ; Flagellin/*genetics ; Light ; Movement ; *Symbiosis ; Vibrio/*physiology ; },
abstract = {The motile bacterium Vibrio fischeri is the specific bacterial symbiont of the Hawaiian squid Euprymna scolopes. Because motility is essential for initiating colonization, we have begun to identify stage-specific motility requirements by creating flagellar mutants that have symbiotic defects. V. fischeri has six flagellin genes that are uniquely arranged in two chromosomal loci, flaABCDE and flaF. With the exception of the flaA product, the predicted gene products are more similar to each other than to flagellins of other Vibrio species. Immunoblot analysis indicated that only five of the six predicted proteins were present in purified flagella, suggesting that one protein, FlaF, is unique with respect to either its regulation or its function. We created mutations in two genes, flaA and flaC. Compared to a flaC mutant, which has wild-type flagellation, a strain having a mutation in the flaA gene has fewer flagella per cell and exhibits a 60% decrease in its rate of migration in soft agar. During induction of light organ symbiosis, colonization by the flaA mutant is impaired, and this mutant is severely outcompeted when it is presented to the animal as a mixed inoculum with the wild-type strain. Furthermore, flaA mutant cells are preferentially expelled from the animal, suggesting either that FlaA plays a role in adhesion or that normal motility is an advantage for retention within the host. Taken together, these results show that the flagellum of V. fischeri is a complex structure consisting of multiple flagellin subunits, including FlaA, which is essential both for normal flagellation and for motility, as well as for effective symbiotic colonization.},
}
@article {pmid15175301,
year = {2004},
author = {Lupp, C and Ruby, EG},
title = {Vibrio fischeri LuxS and AinS: comparative study of two signal synthases.},
journal = {Journal of bacteriology},
volume = {186},
number = {12},
pages = {3873-3881},
doi = {10.1128/JB.186.12.3873-3881.2004},
pmid = {15175301},
issn = {0021-9193},
support = {R01 RR012294/RR/NCRR NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Bacterial Proteins/genetics/*metabolism ; Carbon-Sulfur Lyases ; Culture Media ; Decapodiformes/microbiology ; *Gene Expression Regulation, Bacterial ; Homoserine/*analogs & derivatives/genetics/metabolism ; Lactones/metabolism ; Luminescent Measurements ; Mutation ; *Signal Transduction ; Symbiosis ; Transcription, Genetic ; Vibrio/*enzymology/genetics/*growth & development ; },
abstract = {Vibrio fischeri possesses two acyl-homoserine lactone quorum-sensing systems, ain and lux, both of which are involved in the regulation of luminescence gene expression and are required for persistent colonization of the squid host, Euprymna scolopes. We have previously demonstrated that the ain system induces luminescence at cell densities that precede lux system activation. Our data suggested that the ain system both relieves repression and initially induces the lux system, thereby achieving sequential induction of gene expression by these two systems. Analysis of the V. fischeri genome revealed the presence of a putative third system based on the enzyme LuxS, which catalyzes the synthesis of the Vibrio harveyi autoinducer 2 (AI-2). In this study, we investigated the impact of V. fischeri LuxS on luminescence and colonization competence in comparison to that of the ain system. Similar to the ain system, inactivation of the AI-2 system decreased light production in culture, but not in the squid host. However, while an ainS mutant produces no detectable light in culture, a luxS mutant expressed approximately 70% of wild-type luminescence levels. A mutation in luxS alone did not compromise symbiotic competence of V. fischeri; however, levels of colonization of an ainS luxS double mutant were reduced to 50% of the already diminished level of ainS mutant colonization, suggesting that these two systems regulate colonization gene expression synergistically through a common pathway. Introduction of a luxO mutation into the luxS and ainS luxS background could relieve both luminescence and colonization defects, consistent with a model in which LuxS, like AinS, regulates gene expression through LuxO. Furthermore, while luxS transcription appeared to be constitutive and the AI-2 signal concentration did not change dramatically, our data suggest that ainS transcription is autoregulated, resulting in an over 2,000-fold increase in signal concentration as culture density increased. Taken together, these data indicate that V. fischeri LuxS affects both luminescence regulation and colonization competence; however, its quantitative contribution is small when compared to that of the AinS signal.},
}
@article {pmid15108817,
year = {2004},
author = {Nishiguchi, MK and Lopez, JE and Boletzky, Sv},
title = {Enlightenment of old ideas from new investigations: more questions regarding the evolution of bacteriogenic light organs in squids.},
journal = {Evolution & development},
volume = {6},
number = {1},
pages = {41-49},
pmid = {15108817},
issn = {1520-541X},
support = {R25 GM061222/GM/NIGMS NIH HHS/United States ; GM61222-01/GM/NIGMS NIH HHS/United States ; S06 GM008136/GM/NIGMS NIH HHS/United States ; SO6-GM08136-26/GM/NIGMS NIH HHS/United States ; SC1 AI081659/AI/NIAID NIH HHS/United States ; },
mesh = {Animal Structures/*embryology ; Animals ; Base Sequence ; *Biological Evolution ; DNA Primers ; DNA, Mitochondrial/genetics ; DNA, Ribosomal/genetics ; Decapodiformes/*anatomy & histology/*genetics/microbiology ; Embryonic Induction/physiology ; Histological Techniques ; *Luminescent Measurements ; Molecular Sequence Data ; Morphogenesis ; Oceans and Seas ; *Phylogeny ; Sequence Analysis, DNA ; *Symbiosis ; Vibrionaceae/physiology ; },
abstract = {Bioluminescence is widespread among many different types of marine organisms. Metazoans contain two types of luminescence production, bacteriogenic (symbiotic with bacteria) or autogenic, via the production of a luminous secretion or the intrinsic properties of luminous cells. Several species in two families of squids, the Loliginidae and the Sepiolidae (Mollusca: Cephalopoda) harbor bacteriogenic light organs that are found central in the mantle cavity. These light organs are exceptional in function, that is, the morphology and the complexity suggests that the organ has evolved to enhance and direct light emission from bacteria that are harbored inside. Although light organs are widespread among taxa within the Sepiolidae, the origin and development of this important feature is not well studied. We compared light organ morphology from several closely related taxa within the Sepiolidae and combined molecular phylogenetic data using four loci (nuclear ribosomal 28S rRNA and the mitochondrial cytochrome c oxidase subunit I and 12S and 16S rRNA) to determine whether this character was an ancestral trait repeatedly lost among both families or whether it evolved independently as an adaptation to the pelagic and benthic lifestyles. By comparing other closely related extant taxa that do not contain symbiotic light organs, we hypothesized that the ancestral state of sepiolid light organs most likely evolved from part of a separate accessory gland open to the environment that allowed colonization of bacteria to occur and further specialize in the eventual development of the modern light organ.},
}
@article {pmid15090534,
year = {2004},
author = {Stabb, EV and Butler, MS and Adin, DM},
title = {Correlation between osmolarity and luminescence of symbiotic Vibrio fischeri strain ES114.},
journal = {Journal of bacteriology},
volume = {186},
number = {9},
pages = {2906-2908},
pmid = {15090534},
issn = {0021-9193},
support = {R01 AI050661/AI/NIAID NIH HHS/United States ; R01 AI 50661/AI/NIAID NIH HHS/United States ; },
mesh = {Culture Media ; *Luminescent Measurements ; Osmolar Concentration ; Promoter Regions, Genetic ; Repressor Proteins/genetics ; Sodium Chloride/*pharmacology ; *Symbiosis ; Trans-Activators/genetics ; Vibrio/genetics/*physiology ; },
abstract = {Vibrio fischeri isolates from Euprymna scolopes are dim in culture but bright in the host. We found the luminescence of V. fischeri to be correlated with external osmolarity both in culture and in this symbiosis. Luminescence enhancement by osmolarity was independent of the lux promoter and unaffected by autoinducers or the level of lux expression, but the addition of an aldehyde substrate for luciferase raised the luminescence of cells grown at high and low osmolarities to the same high level. V. fischeri culture media have lower osmolarities than are typical in seawater or in cephalopods, partially accounting for the bacterium's low light output in culture.},
}
@article {pmid15066853,
year = {2004},
author = {Wolfe, AJ and Millikan, DS and Campbell, JM and Visick, KL},
title = {Vibrio fischeri sigma54 controls motility, biofilm formation, luminescence, and colonization.},
journal = {Applied and environmental microbiology},
volume = {70},
number = {4},
pages = {2520-2524},
pmid = {15066853},
issn = {0099-2240},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {Biofilms/growth & development ; *DNA-Binding Proteins ; DNA-Directed RNA Polymerases/genetics/*physiology ; Genes, Bacterial ; Iron/metabolism ; Luminescence ; Molecular Sequence Data ; Movement ; Mutation ; Nitrogen/metabolism ; Plasmids/genetics ; RNA Polymerase Sigma 54 ; Sigma Factor/genetics/*physiology ; Vibrio/genetics/*physiology ; },
abstract = {In this study, we demonstrated that the putative Vibrio fischeri rpoN gene, which encodes sigma(54), controls flagellar biogenesis, biofilm development, and bioluminescence. We also show that rpoN plays a requisite role initiating the symbiotic association of V. fischeri with juveniles of the squid Euprymna scolopes.},
}
@article {pmid15006763,
year = {2004},
author = {Kimbell, JR and McFall-Ngai, MJ},
title = {Symbiont-induced changes in host actin during the onset of a beneficial animal-bacterial association.},
journal = {Applied and environmental microbiology},
volume = {70},
number = {3},
pages = {1434-1441},
pmid = {15006763},
issn = {0099-2240},
support = {R01 AI050611/AI/NIAID NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; AI 50611/AI/NIAID NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Actins/genetics/*metabolism ; Animals ; Base Sequence ; Cytoskeleton/metabolism ; Decapodiformes/anatomy & histology/genetics/*metabolism/*microbiology ; Epithelium/metabolism ; Gene Expression ; In Situ Hybridization ; Models, Biological ; RNA, Messenger/genetics/metabolism ; Symbiosis/genetics/*physiology ; Vibrio/*metabolism ; },
abstract = {The influence of bacteria on the cytoskeleton of animal cells has been studied extensively only in pathogenic associations. We characterized changes in host cytoskeletal actin induced by the bacterial partner during the onset of a cooperative animal-bacteria association using the squid-vibrio model. Two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis revealed that Vibrio fischeri induced a dramatic increase in actin protein abundance in the bacteria-associated host tissues during the onset of the symbiosis. Immunocytochemistry revealed that this change in actin abundance correlated with a two- to threefold increase in actin in the apical cell surface of the epithelium-lined ducts, the route of entry of symbionts into host tissues. Real-time reverse transcriptase PCR and in situ hybridization did not detect corresponding changes in actin mRNA. Temporally correlated with the bacteria-induced changes in actin levels was a two- to threefold decrease in duct circumference, a 20% loss in the average number of cells interfacing with the duct lumina, and dramatic changes in duct cell shape. When considered with previous studies of the biomechanical and biochemical characteristics of the duct, these findings suggest that the bacterial symbionts, upon colonizing the host organ, induce modifications that physically and chemically limit the opportunity for subsequent colonizers to pass through the ducts. Continued study of the squid-vibrio system will allow further comparisons of the mechanisms by which pathogenic and cooperative bacteria influence cytoskeleton dynamics in host cells.},
}
@article {pmid14660408,
year = {2003},
author = {DeLoney-Marino, CR and Wolfe, AJ and Visick, KL},
title = {Chemoattraction of Vibrio fischeri to serine, nucleosides, and N-acetylneuraminic acid, a component of squid light-organ mucus.},
journal = {Applied and environmental microbiology},
volume = {69},
number = {12},
pages = {7527-7530},
pmid = {14660408},
issn = {0099-2240},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {*Animal Structures ; Animals ; Carbohydrates ; *Chemotaxis ; Culture Media ; Decapodiformes/*microbiology ; *Light ; Mucus/*chemistry ; N-Acetylneuraminic Acid/physiology ; Nucleosides/physiology ; Serine/physiology ; Symbiosis ; Vibrio/growth & development/*physiology ; },
abstract = {Newly hatched juveniles of the Hawaiian squid Euprymna scolopes rapidly become colonized by the bioluminescent marine bacterium Vibrio fischeri. Motility is required to establish the symbiotic colonization, but the role of chemotaxis is unknown. In this study we analyzed chemotaxis of V. fischeri to a number of potential attractants. The bacterium migrated toward serine and most sugars tested. V. fischeri also exhibited the unusual ability to migrate to nucleosides and nucleotides as well as to N-acetylneuraminic acid, a component of squid mucus.},
}
@article {pmid14645281,
year = {2003},
author = {Whistler, CA and Ruby, EG},
title = {GacA regulates symbiotic colonization traits of Vibrio fischeri and facilitates a beneficial association with an animal host.},
journal = {Journal of bacteriology},
volume = {185},
number = {24},
pages = {7202-7212},
pmid = {14645281},
issn = {0021-9193},
support = {R01 RR012294/RR/NCRR NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {4-Butyrolactone/*analogs & derivatives/metabolism ; Aldehydes/metabolism ; Amino Acids/metabolism ; Animals ; Bacterial Proteins/genetics/*metabolism ; Cloning, Molecular ; Decapodiformes/*microbiology ; Genetic Complementation Test ; Luminescent Measurements ; Microbiological Techniques ; Mutagenesis ; *Symbiosis ; Vibrio/genetics/*growth & development/*metabolism ; },
abstract = {The GacS/GacA two-component system regulates the expression of bacterial traits during host association. Although the importance of GacS/GacA as a regulator of virulence is well established, its role in benign associations is not clear, as mutations in either the gacS or gacA gene have little impact on the success of colonization in nonpathogenic associations studied thus far. Using as a model the symbiotic association of the bioluminescent marine bacterium Vibrio fischeri with its animal host, the Hawaiian bobtail squid, Euprymna scolopes, we investigated the role of GacA in this beneficial animal-microbe interaction. When grown in culture, gacA mutants were defective in several traits important for symbiosis, including luminescence, growth in defined media, growth yield, siderophore activity, and motility. However, gacA mutants were not deficient in production of acylated homoserine lactone signals or catalase activity. The ability of the gacA mutants to initiate squid colonization was impaired but not abolished, and they reached lower-than-wild-type population densities within the host light organ. In contrast to their dark phenotype in culture, gacA mutants that reached population densities above the luminescence detection limit had normal levels of luminescence per bacterial cell in squid light organs, indicating that GacA is not required for light production within the host. The gacA mutants were impaired at competitive colonization and could only successfully cocolonize squid light organs when present in the seawater at higher inoculum densities than wild-type bacteria. Although severely impaired during colonization initiation, gacA mutants were not displaced by the wild-type strain in light organs that were colonized with both strains. This study establishes the role of GacA as a regulator of a beneficial animal-microbe association and indicates that GacA regulates utilization of growth substrates as well as other colonization traits.},
}
@article {pmid14532046,
year = {2003},
author = {McCann, J and Stabb, EV and Millikan, DS and Ruby, EG},
title = {Population dynamics of Vibrio fischeri during infection of Euprymna scolopes.},
journal = {Applied and environmental microbiology},
volume = {69},
number = {10},
pages = {5928-5934},
pmid = {14532046},
issn = {0099-2240},
support = {R01 RR012294/RR/NCRR NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animal Structures/microbiology ; Animals ; Base Sequence ; Colony Count, Microbial ; DNA Transposable Elements ; Decapodiformes/*microbiology ; Light ; Molecular Sequence Data ; Mutagenesis, Insertional ; Symbiosis ; Vibrio/genetics/*growth & development/*pathogenicity ; },
abstract = {The luminous bacterium Vibrio fischeri colonizes a specialized light-emitting organ within its squid host, Euprymna scolopes. Newly hatched juvenile squid must acquire their symbiont from ambient seawater, where the bacteria are present at low concentrations. To understand the population dynamics of V. fischeri during colonization more fully, we used mini-Tn7 transposons to mark bacteria with antibiotic resistance so that the growth of their progeny could be monitored. When grown in culture, there was no detectable metabolic burden on V. fischeri cells carrying the transposon, which inserts in single copy in a specific intergenic region of the V. fischeri genome. Strains marked with mini-Tn7 also appeared to be equivalent to the wild type in their ability to infect and multiply within the host during coinoculation experiments. Studies of the early stages of colonization suggested that only a few bacteria became associated with symbiotic tissue when animals were exposed for a discrete period (3 h) to an inoculum of V. fischeri cells equivalent to natural population levels; nevertheless, all these hosts became infected. When three differentially marked strains of V. fischeri were coincubated with juvenile squid, the number of strains recovered from an individual symbiotic organ was directly dependent on the size of the inoculum. Further, these results indicated that, when exposed to low numbers of V. fischeri, the host may become colonized by only one or a few bacterial cells, suggesting that symbiotic infection is highly efficient.},
}
@article {pmid14507383,
year = {2003},
author = {Lupp, C and Urbanowski, M and Greenberg, EP and Ruby, EG},
title = {The Vibrio fischeri quorum-sensing systems ain and lux sequentially induce luminescence gene expression and are important for persistence in the squid host.},
journal = {Molecular microbiology},
volume = {50},
number = {1},
pages = {319-331},
pmid = {14507383},
issn = {0950-382X},
support = {RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Bacterial Proteins/*metabolism ; Decapodiformes/microbiology ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Genes, Bacterial ; Homoserine/analogs & derivatives ; Luminescent Measurements ; Mutagenesis, Insertional ; Mutation ; Signal Transduction/*physiology ; Symbiosis/physiology ; Vibrio/genetics/*growth & development/*physiology ; },
abstract = {Bacterial quorum sensing using acyl-homoserine lactones (acyl-HSLs) as cell-density dependent signalling molecules is important for the transcriptional regulation of many genes essential in the establishment and the maintenance of bacteria-host associations. Vibrio fischeri, the symbiotic partner of the Hawaiian bobtail squid Euprymna scolopes, possesses two distinct acyl-HSL synthase proteins, LuxI and AinS. Whereas the cell density-dependent regulation of luminescence by the LuxI-produced signal is a well-described phenomenon, and its role in light organ symbiosis has been defined, little is known about the ain system. We have investigated the impact of the V. fischeri acyl-HSL synthase AinS on both luminescence and symbiotic colonization. Through phenotypic studies of V. fischeri mutants we have found that the AinS-signal is the predominant inducer of luminescence expression in culture, whereas the impact of the LuxI-signal is apparent only at the high cell densities occurring in symbiosis. Furthermore, our studies revealed that ainS regulates activities essential for successful colonization of E. scolopes, i.e. the V. fischeri ainS mutant failed to persist in the squid light organ. Mutational inactivation of the transcriptional regulator protein LuxO in the ainS mutant partially or completely reversed all the observed phenotypes, demonstrating that the AinS-signal regulates expression of downstream genes through the inactivation of LuxO. Taken together, our results suggest that the two quorum-sensing systems in V. fischeri, ain and lux, sequentially induce the expression of luminescence genes and possibly other colonization factors.},
}
@article {pmid14503724,
year = {2003},
author = {Hara-Kudo, Y and Kasuga, Y and Kiuchi, A and Horisaka, T and Kawasumi, T and Kumagai, S},
title = {Increased sensitivity in PCR detection of tdh-positive Vibrio parahaemolyticus in seafood with purified template DNA.},
journal = {Journal of food protection},
volume = {66},
number = {9},
pages = {1675-1680},
pmid = {14503724},
issn = {0362-028X},
mesh = {Animals ; Bacterial Proteins ; DNA, Bacterial/analysis ; Food Contamination/analysis ; Food Microbiology ; Gene Amplification ; Genes, Bacterial ; Hemolysin Proteins/genetics/*isolation & purification ; Humans ; Polymerase Chain Reaction/*methods ; Seafood/*microbiology ; Sensitivity and Specificity ; Vibrio parahaemolyticus/genetics/*isolation & purification/pathogenicity ; },
abstract = {PCR is an important method for the detection of thermostable direct hemolysin gene (tdh)-positive (pathogenic hemolysin-producing) strains of Vibrio parahaemolyticus in seafood because tdh-negative (nonpathogenic) V. parahaemolyticus strains often contaminate seafood and interfere with the direct isolation of tdh-positive V. parahaemolyticus. In this study, the use of PCR to detect the tdh gene of V. parahaemolyticus in various seafoods artificially contaminated with tdh-positive V. parahaemolyticus was examined. PCR was inhibited by substances in oysters, squid, mackerel, and yellowtail but not by cod, sea bream, scallop, short-necked clam, and shrimp. To improve detection, DNA was purified by either the silica membrane method, the glass fiber method, or the magnetic separation method, and the purified DNA was used as the PCR primer template. For all samples, the use of the silica membrane method and the glass fiber method increased detection sensitivity. The results of this study demonstrate that the use of properly purified template DNA for PCR markedly increases the effectiveness of the method in detecting pathogenic tdh-positive V. parahaemolyticus in contaminated seafood.},
}
@article {pmid12839763,
year = {2003},
author = {Nyholm, SV and McFall-Ngai, MJ},
title = {Dominance of Vibrio fischeri in secreted mucus outside the light organ of Euprymna scolopes: the first site of symbiont specificity.},
journal = {Applied and environmental microbiology},
volume = {69},
number = {7},
pages = {3932-3937},
pmid = {12839763},
issn = {0099-2240},
support = {R01 AI050611/AI/NIAID NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; AI 50611/AI/NIAID NIH HHS/United States ; RR 12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animal Structures ; Animals ; Decapodiformes/*growth & development/*microbiology ; Ecosystem ; Green Fluorescent Proteins ; Light ; Luminescent Proteins/genetics/metabolism ; Mucus/*microbiology ; Organ Specificity ; Species Specificity ; *Symbiosis ; Vibrio/*growth & development/isolation & purification/metabolism ; },
abstract = {Previous studies of the Euprymna scolopes-Vibrio fischeri symbiosis have demonstrated that, during colonization, the hatchling host secretes mucus in which gram-negative environmental bacteria amass in dense aggregations outside the sites of infection. In this study, experiments with green fluorescent protein-labeled symbiotic and nonsymbiotic species of gram-negative bacteria were used to characterize the behavior of cells in the aggregates. When hatchling animals were exposed to 10(3) to 10(6) V. fischeri cells/ml added to natural seawater, which contains a mix of approximately 10(6) nonspecific bacterial cells/ml, V. fischeri cells were the principal bacterial cells present in the aggregations. Furthermore, when animals were exposed to equal cell numbers of V. fischeri (either a motile or a nonmotile strain) and either Vibrio parahaemolyticus or Photobacterium leiognathi, phylogenetically related gram-negative bacteria that also occur in the host's habitat, the symbiont cells were dominant in the aggregations. The presence of V. fischeri did not compromise the viability of these other species in the aggregations, and no significant growth of V. fischeri cells was detected. These findings suggested that dominance results from the ability of V. fischeri either to accumulate or to be retained more effectively within the mucus. Viability of the V. fischeri cells was required for both the formation of tight aggregates and their dominance in the mucus. Neither of the V. fischeri quorum-sensing compounds accumulated in the aggregations, which suggested that the effects of these small signal molecules are not critical to V. fischeri dominance. Taken together, these data provide evidence that the specificity of the squid-vibrio symbiosis begins early in the interaction, in the mucus where the symbionts aggregate outside of the light organ.},
}
@article {pmid12775692,
year = {2003},
author = {Millikan, DS and Ruby, EG},
title = {FlrA, a sigma54-dependent transcriptional activator in Vibrio fischeri, is required for motility and symbiotic light-organ colonization.},
journal = {Journal of bacteriology},
volume = {185},
number = {12},
pages = {3547-3557},
pmid = {12775692},
issn = {0021-9193},
support = {R01 RR012294/RR/NCRR NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Amino Acid Sequence ; Animals ; Base Sequence ; Cloning, Molecular ; *DNA-Binding Proteins ; *DNA-Directed RNA Polymerases/metabolism ; Decapodiformes ; Flagella/*genetics ; *Genes, Bacterial ; Genetic Complementation Test ; Light ; Molecular Sequence Data ; Movement ; Mutation ; Promoter Regions, Genetic ; RNA Polymerase Sigma 54 ; Regulon ; Sequence Alignment ; *Sigma Factor/metabolism ; Symbiosis ; Trans-Activators/*genetics ; Vibrio/*genetics ; },
abstract = {Flagellum-mediated motility of Vibrio fischeri is an essential factor in the bacterium's ability to colonize its host, the Hawaiian squid Euprymna scolopes. To begin characterizing the nature of the flagellar regulon, we have cloned a gene, designated flrA, from V. fischeri that encodes a putative sigma(54)-dependent transcriptional activator. Genetic arrangement of the flrA locus in V. fischeri is similar to motility master-regulator operons of Vibrio cholerae and Vibrio parahaemolyticus. In addition, examination of regulatory regions of a number of flagellar operons in V. fischeri revealed apparent sigma(54) recognition motifs, suggesting that the flagellar regulatory hierarchy is controlled by a similar mechanism to that described in V. cholerae. However, in contrast to its closest known relatives, flrA mutant strains of V. fischeri ES114 were completely abolished in swimming capability. Although flrA provided in trans restored motility to the flrA mutant, the complemented strain was unable to reach wild-type levels of symbiotic colonization in juvenile squid, suggesting a possible role for the proper expression of FlrA in regulating symbiotic colonization factors in addition to those required for motility. Comparative RNA arbitrarily primed PCR analysis of the flrA mutant and its wild-type parent revealed several differentially expressed transcripts. These results define a regulon that includes both flagellar structural genes and other genes apparently not involved in flagellum elaboration or function. Thus, the transcriptional activator FlrA plays an essential role in regulating motility, and apparently in modulating other symbiotic functions, in V. fischeri.},
}
@article {pmid21680430,
year = {2003},
author = {Kimbell, JR and McFall-Ngai, MJ},
title = {The squid-Vibrio symbioses: from demes to genes.},
journal = {Integrative and comparative biology},
volume = {43},
number = {2},
pages = {254-260},
doi = {10.1093/icb/43.2.254},
pmid = {21680430},
issn = {1540-7063},
abstract = {The monospecific light organ association between the Hawaiian sepiolid squid Euprymna scolopes and the marine luminous bacterium Vibrio fischeri has been used as a model for the study of the most common type of coevolved animal-bacterial interaction; i.e., the association of Gram-negative bacteria with the extracellular apical surfaces of polarized epithelia. Analysis of the squid-vibrio symbiosis has ranged from characterizations of the harvesting mechanisms by which the host ensures colonization by the appropriate symbiont to identification of bacteria-induced changes in host gene expression that accompany the establishment and maintenance of the relationship. Studies of this model have been enhanced by extensive collaboration with microbiologists, who are able to manipulate the genetics of the bacterial symbiont. The results of our studies have indicated that initiation and persistence of the association requires a complex, reciprocal molecular dialogue between these two phylogenetically distant partners.},
}
@article {pmid12644650,
year = {2003},
author = {Shaw, SL and Long, SR},
title = {Nod factor elicits two separable calcium responses in Medicago truncatula root hair cells.},
journal = {Plant physiology},
volume = {131},
number = {3},
pages = {976-984},
doi = {10.1104/pp.005546},
pmid = {12644650},
issn = {0032-0889},
mesh = {Biological Transport/drug effects ; Calcium/*metabolism ; Calcium Signaling/drug effects ; Cytoplasm/drug effects ; Lipopolysaccharides/*pharmacology ; Medicago/drug effects/genetics/*microbiology ; Mutation ; Plant Roots/cytology/*drug effects/microbiology ; Signal Transduction/drug effects/physiology ; Symbiosis/*drug effects/physiology ; },
abstract = {Modulation of intracellular calcium levels plays a key role in the transduction of many biological signals. Here, we characterize early calcium responses of wild-type and mutant Medicago truncatula plants to nodulation factors produced by the bacterial symbiont Sinorhizobium meliloti using a dual-dye ratiometric imaging technique. When presented with 1 nM Nod factor, root hair cells exhibited only the previously described calcium spiking response initiating 10 min after application. Nod factor (10 nM) elicited an immediate increase in calcium levels that was temporally earlier and spatially distinct from calcium spikes occurring later in the same cell. Nod factor analogs that were structurally related, applied at 10 nM, failed to initiate this calcium flux response. Cells induced to spike with low Nod factor concentrations show a calcium flux response when Nod factor is raised from 1 to 10 nM. Plant mutants previously shown to be deficient for the calcium spiking response (dmi1 and dmi2) exhibited an immediate, truncated calcium flux with 10 nM Nod factor, demonstrating a competence to respond to Nod factor but an impaired ability to generate a full biphasic response. These results demonstrate that the legume root hair cell exhibits two independent calcium responses to Nod factor triggered at different agonist concentrations and suggests an early branch point in the Nod factor signal transduction pathway.},
}
@article {pmid12571000,
year = {2003},
author = {Stabb, EV and Ruby, EG},
title = {Contribution of pilA to competitive colonization of the squid Euprymna scolopes by Vibrio fischeri.},
journal = {Applied and environmental microbiology},
volume = {69},
number = {2},
pages = {820-826},
pmid = {12571000},
issn = {0099-2240},
support = {F32 GM020041/GM/NIGMS NIH HHS/United States ; GM20041/GM/NIGMS NIH HHS/United States ; },
mesh = {Amino Acid Sequence ; Animal Structures/microbiology ; Animals ; Bacterial Proteins/*genetics/*metabolism ; DNA-Binding Proteins/*genetics/*metabolism ; Decapodiformes/*microbiology ; *Fimbriae Proteins ; Light ; Molecular Sequence Data ; Mutation ; Sequence Analysis, DNA ; *Symbiosis ; Vibrio/*growth & development/physiology ; },
abstract = {Vibrio fischeri colonizes the squid Euprymna scolopes in a mutualistic symbiosis. Hatchling squid lack these bacterial symbionts, and V. fischeri strains must compete to occupy this privileged niche. We cloned a V. fischeri gene, designated pilA, that contributes to colonization competitiveness and encodes a protein similar to type IV-A pilins. Unlike its closest known relatives, Vibrio cholerae mshA and vcfA, pilA is monocistronic and not clustered with genes associated with pilin export or assembly. Using wild-type strain ES114 as the parent, we generated an in-frame pilA deletion mutant, as well as pilA mutants marked with a kanamycin resistance gene. In mixed inocula, marked mutants were repeatedly outcompeted by ES114 (P < 0.05) but not by an unmarked pilA mutant, for squid colonization. In contrast, the ratio of mutant to ES114 CFUs did not change during 70 generations of coculturing. The competitive defect of pilA mutants ranged from 1.7- to 10-fold and was more pronounced when inocula were within the range estimated for V. fischeri populations in Hawaiian seawater (200 to 2,000 cells/ml) than when higher densities were used. ES114 also outcompeted a pilA mutant by an average of twofold at lower inoculum densities, when only a fraction of the squid became infected, most by only one strain. V. fischeri strain ET101, which was isolated from Euprymna tasmanica and is outcompeted by ES114, lacks pilA; however, 11 other diverse V. fischeri isolates apparently possess pilA. The competitive defect of pilA mutants suggests that cell surface molecules may play important roles in the initiation of beneficial symbioses in which animals must acquire symbionts from a mixed community of environmental bacteria.},
}
@article {pmid12471505,
year = {2002},
author = {Lupp, C and Hancock, RE and Ruby, EG},
title = {The Vibrio fischeri sapABCDF locus is required for normal growth, both in culture and in symbiosis.},
journal = {Archives of microbiology},
volume = {179},
number = {1},
pages = {57-65},
doi = {10.1007/s00203-002-0502-7},
pmid = {12471505},
issn = {0302-8933},
support = {RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Base Sequence ; Cell Membrane/metabolism ; Cloning, Molecular ; Culture Media ; Decapodiformes/*genetics/microbiology ; Models, Genetic ; Mutation ; Phenotype ; Quantitative Trait Loci ; Sequence Homology, Nucleic Acid ; *Symbiosis ; Vibrio/*genetics/*growth & development/physiology ; },
abstract = {Inactivation of the sapABCDF genes results in a loss of virulence in several bacterial pathogens of animals and plants. The role of this locus in the growth physiology of Vibrio fischeri, and in the symbiotic colonization of the squid Euprymna scolopes was investigated. In rich medium, a V. fischeri sapA insertion mutant grew at only 85% the rate of its wild-type parent. While a similar effect has been attributed to a potassium-transport defect in sap mutants of enteric bacteria, the V. fischeri mutant grew more slowly regardless of the potassium concentration of the medium. Similarly, the growth-rate defect was independent of the source of either carbon, nitrogen, or phosphorous, indicating that the V. fischeri sap genes do not encode functions required for the transport of a specific form of any of these nutrients. Finally, while a delay in colonizing the nascent light organ of the squid could be accounted for by the lower growth rate of the mutant, a small but statistically significant reduction in its final population size in the host, but not in medium, suggests that the sap genes play another role in the symbiosis. All of these phenotypic defects could be genetically complemented in trans by the sapABCDF genes, but not by the sapA gene alone, indicating that the insertion in sapA is polar to the four downstream genes in the locus. Thus, while the sap locus is important to the normal growth of V. fischeri, it plays different physiological roles in growth and tissue colonization than it does in enteric pathogens.},
}
@article {pmid12324362,
year = {2002},
author = {Nyholm, SV and Deplancke, B and Gaskins, HR and Apicella, MA and McFall-Ngai, MJ},
title = {Roles of Vibrio fischeri and nonsymbiotic bacteria in the dynamics of mucus secretion during symbiont colonization of the Euprymna scolopes light organ.},
journal = {Applied and environmental microbiology},
volume = {68},
number = {10},
pages = {5113-5122},
pmid = {12324362},
issn = {0099-2240},
support = {R01 RR012294/RR/NCRR NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Behavior, Animal/physiology ; Cilia ; Decapodiformes/embryology/*microbiology ; Epithelium/growth & development ; Female ; Luminescent Measurements ; Male ; Morphogenesis ; Symbiosis/*physiology ; Vibrio/*physiology ; },
abstract = {During light organ colonization of the squid Euprymna scolopes by Vibrio fischeri, host-derived mucus provides a surface upon which environmental V. fischeri forms a biofilm and aggregates prior to colonization. In this study we defined the temporal and spatial characteristics of this process. Although permanent colonization is specific to certain strains of V. fischeri, confocal microscopy analyses revealed that light organ crypt spaces took up nonspecific bacteria and particles that were less than 2 micro m in diameter during the first hour after hatching. However, within 2 h after inoculation, these cells or particles were not detectable, and further entry by nonspecific bacteria or particles appeared to be blocked. Exposure to environmental gram-negative or -positive bacteria or bacterial peptidoglycan caused the cells of the organ's superficial ciliated epithelium to release dense mucin stores at 1 to 2 h after hatching that were used to form the substrate upon which V. fischeri formed a biofilm and aggregated. Whereas the uncolonized organ surface continued to shed mucus, within 48 h of symbiont colonization mucus shedding ceased and the formation of bacterial aggregations was no longer observed. Eliminating the symbiont from the crypts with antibiotics restored the ability of the ciliated fields to secrete mucus and aggregate bacteria. While colonization by V. fischeri inhibited mucus secretion by the surface epithelium, secretion of host-derived mucus was induced in the crypt spaces. Together, these data indicate that although initiation of mucus secretion from the superficial epithelium is nonspecific, the inhibition of mucus secretion in these cells and the concomitant induction of secretion in the crypt cells are specific to natural colonization by V. fischeri.},
}
@article {pmid12193629,
year = {2002},
author = {DeLoney, CR and Bartley, TM and Visick, KL},
title = {Role for phosphoglucomutase in Vibrio fischeri-Euprymna scolopes symbiosis.},
journal = {Journal of bacteriology},
volume = {184},
number = {18},
pages = {5121-5129},
pmid = {12193629},
issn = {0021-9193},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; GM59690/GM/NIGMS NIH HHS/United States ; },
mesh = {Animals ; Culture Media ; DNA Transposable Elements ; Decapodiformes/*microbiology ; Gene Library ; Luminescent Measurements ; Molecular Sequence Data ; Mutation ; Phosphoglucomutase/chemistry/genetics/*metabolism ; *Symbiosis ; Vibrio/*enzymology/genetics/*growth & development/physiology ; },
abstract = {Vibrio fischeri, a luminescent marine bacterium, specifically colonizes the light organ of its symbiotic partner, the Hawaiian squid Euprymna scolopes. In a screen for V. fischeri colonization mutants, we identified a strain that exhibited on average a 10-fold decrease in colonization levels relative to that achieved by wild-type V. fischeri. Further characterization revealed that this defect did not result from reduced luminescence or motility, two processes required for normal colonization. We determined that the transposon in this mutant disrupted a gene with high sequence identity to the pgm (phosphoglucomutase) gene of Escherichia coli, which encodes an enzyme that functions in both galactose metabolism and the synthesis of UDP-glucose. The V. fischeri mutant grew poorly with galactose as a sole carbon source and was defective for phosphoglucomutase activity, suggesting functional identity between E. coli Pgm and the product of the V. fischeri gene, which was therefore designated pgm. In addition, lipopolysaccharide profiles of the mutant were distinct from that of the parent strain and the mutant exhibited increased sensitivity to various cationic agents and detergents. Chromosomal complementation with the wild-type pgm allele restored the colonization ability to the mutant and also complemented the other noted defects. Unlike the pgm mutant, a galactose-utilization mutant (galK) of V. fischeri colonized juvenile squid to wild-type levels, indicating that the symbiotic defect of the pgm mutant is not due to an inability to catabolize galactose. Thus, pgm represents a new gene required for promoting colonization of E. scolopes by V. fischeri.},
}
@article {pmid12100554,
year = {2002},
author = {Fidopiastis, PM and Miyamoto, CM and Jobling, MG and Meighen, EA and Ruby, EG},
title = {LitR, a new transcriptional activator in Vibrio fischeri, regulates luminescence and symbiotic light organ colonization.},
journal = {Molecular microbiology},
volume = {45},
number = {1},
pages = {131-143},
pmid = {12100554},
issn = {0950-382X},
support = {RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Amino Acid Sequence ; Animals ; Bacterial Proteins/chemistry/metabolism ; Decapodiformes/anatomy & histology/*microbiology ; *Gene Expression Regulation, Bacterial ; Light ; *Luminescent Measurements ; Molecular Sequence Data ; Repressor Proteins/genetics/metabolism ; Sequence Analysis, DNA ; *Symbiosis ; Trans-Activators/chemistry/genetics/*metabolism ; Vibrio/genetics/growth & development/metabolism/*physiology ; },
abstract = {Vibrio fischeri is the bacterial symbiont within the light-emitting organ of the sepiolid squid Euprymna scolopes. Upon colonizing juvenile squids, bacterial symbionts grow on host-supplied nutrients, while providing a bioluminescence that the host uses during its nocturnal activities. Mutant bacterial strains that are unable to emit light have been shown to be defective in normal colonization. A 606 bp open reading frame was cloned from V. fischeri that encoded a protein, which we named LitR, that had about 60% identity to four related regulator proteins: Vibrio cholerae HapR, Vibrio harveyi LuxR, Vibrio parahaemolyticus OpaR and Vibrio vulnificus SmcR. When grown in culture, cells of V. fischeri strain PMF8, in which litR was insertionally inactivated, were delayed in the onset of luminescence induction and emitted only about 20% as much light per cell as its parent. Protein-binding studies suggested that LitR enhances quorum sensing by regulating the transcription of the luxR gene. Interestingly, when competed against its parent in mixed inocula, PMF8 became the predominant symbiont present in 83% of light organs. Thus, the litR mutation appears to represent a novel class of mutations in which the loss of a regulatory gene function enhances the bacterium's competence in initiating a benign infection.},
}
@article {pmid12019463,
year = {2002},
author = {Nishiguchi, MK},
title = {Host-symbiont recognition in the environmentally transmitted sepiolid squid-Vibrio mutualism.},
journal = {Microbial ecology},
volume = {44},
number = {1},
pages = {10-18},
doi = {10.1007/s00248-002-0002-y},
pmid = {12019463},
issn = {0095-3628},
support = {SO6-GM08136-26/GM/NIGMS NIH HHS/United States ; },
mesh = {Animals ; Biological Evolution ; Decapodiformes/classification/genetics/*microbiology ; Environment ; Luminescent Measurements ; Photobacterium/genetics/*physiology ; Species Specificity ; *Symbiosis ; Time Factors ; Vibrio/genetics/*physiology ; },
abstract = {Associations between environmentally transmitted symbionts and their hosts provide a unique opportunity to study the evolution of specificity and subsequent radiation of tightly coupled host-symbiont assemblages [3, 8, 24]. The evidence provided here from the environmentally transmitted bacterial symbiont Vibrio fischeri and its sepiolid squid host (Sepiolidae: Euprymna) demonstrates how host-symbiont specificity can still evolve without vertical transmission of the symbiont [1]. Infection by intraspecific V. fischeri symbionts exhibited preferential colonization over interspecific V. fischeri symbionts, indicating a high degree of specificity for the native symbiotic strains. Inoculation with symbiotic bacteria from other taxa (monocentrid fish and loliginid squids) produced little or no colonization in two species of Euprymna, despite their presence in the same or similar habitats as these squids. These findings of host specificity between native Vibrios and sepiolid squids provides evidence that the presence of multiple strains of symbionts does not dictate the composition of bacterial symbionts in the host.},
}
@article {pmid11976129,
year = {2002},
author = {Millikan, DS and Ruby, EG},
title = {Alterations in Vibrio fischeri motility correlate with a delay in symbiosis initiation and are associated with additional symbiotic colonization defects.},
journal = {Applied and environmental microbiology},
volume = {68},
number = {5},
pages = {2519-2528},
pmid = {11976129},
issn = {0099-2240},
support = {R01 RR012294/RR/NCRR NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Colony Count, Microbial ; Flagella/physiology ; Luminescence ; Movement/*physiology ; Mutation ; Phenotype ; Symbiosis/*physiology ; Vibrio/genetics/*physiology ; },
abstract = {Motility is required for Vibrio fischeri cells to interact with and specifically colonize the light-emitting organ of their host, the squid Euprymna scolopes. To investigate the influence of motility on the expression of the symbiotic phenotype, we isolated mutants of the squid symbiont V. fischeri ES114 that had altered migration abilities. Spontaneous hyperswimmer (HS) mutants, which migrated more rapidly in soft agar and were hyperflagellated relative to the wild type, were isolated and grouped into three phenotypic classes. All of the HS strains tested, regardless of class, were delayed in symbiosis initiation. This result suggested that the hypermotile phenotype alone contributes to an inability to colonize squid normally. Class III HS strains showed the greatest colonization defect: they colonized squid to a level that was only 0.1 to 10% that achieved by ES114. In addition, class III strains were defective in two capabilities, hemagglutination and luminescence, that have been previously described as colonization factors in V. fischeri. Class II and III mutants also share a mucoid colony morphology; however, class II mutants can colonize E. scolopes to a level that was 40% of that achieved by ES114. Thus, the mucoid phenotype alone does not contribute to the greater defect exhibited by class III strains. When squid were exposed to ES114 and any one of the HS mutant strains as a coinoculation, the parent strain dominated the resulting symbiotic light-organ population. To further investigate the colonization defects of the HS strains, we used confocal laser-scanning microscopy to visualize V. fischeri cells in their initial interaction with E. scolopes tissue. Compared to ES114, HS strains from all three classes were delayed in two behaviors involved in colonization: (i) aggregation on host-derived mucus structures and (ii) migration to the crypts. These results suggest that, while motility is required to initiate colonization, the presence of multiple flagella may actually interfere with normal aggregation and attachment behavior. Furthermore, the pleiotropic nature of class III HS strains provides evidence that motility is coregulated with other symbiotic determinants in V. fischeri.},
}
@article {pmid11924500,
year = {2002},
author = {Nishiguchi, MK},
title = {The use of physiological data to corroborate cospeciation events in symbiosis.},
journal = {EXS},
volume = {},
number = {92},
pages = {237-245},
pmid = {11924500},
issn = {1023-294X},
mesh = {Animals ; Decapodiformes/classification/microbiology/*physiology ; *Phylogeny ; *Symbiosis ; Vibrio/*physiology ; },
abstract = {The symbiotic association between sepiolid squids (Family Sepiolidae) and luminous bacteria (Genus Vibrio) provides an unusually tractable model to study the evolution and speciation of mutualistic partnerships. Both host and symbiont can be cultured separately, providing a new avenue to test phylogenetic congruence through molecular and physiological techniques. Combining both molecular and morphological data as well as measuring the degree of infectivity between closely related pairs can help decipher not only patterns of co-speciation between these tightly linked associations, but can also shed new light on the evolution of specificity and recognition among animal-bacterial associations.},
}
@article {pmid11673429,
year = {2001},
author = {Aeckersberg, F and Lupp, C and Feliciano, B and Ruby, EG},
title = {Vibrio fischeri outer membrane protein OmpU plays a role in normal symbiotic colonization.},
journal = {Journal of bacteriology},
volume = {183},
number = {22},
pages = {6590-6597},
doi = {10.1128/JB.183.22.6590-6597.2001},
pmid = {11673429},
issn = {0021-9193},
support = {R01 RR012294/RR/NCRR NIH HHS/United States ; RR-12294/RR/NCRR NIH HHS/United States ; },
mesh = {Adhesins, Bacterial/chemistry/genetics/*physiology ; Amino Acid Sequence ; Animals ; Animals, Newborn ; Bacterial Outer Membrane Proteins/chemistry/genetics/*physiology ; Decapodiformes/*microbiology ; Electric Organ/microbiology ; Molecular Sequence Data ; Mutation ; Sequence Alignment ; Sequence Homology, Amino Acid ; *Symbiosis ; Vibrio/chemistry/*physiology ; },
abstract = {The nascent light-emitting organ of newly hatched juveniles of the Hawaiian sepiolid squid Euprymna scolopes is specifically colonized by cells of Vibrio fischeri that are obtained from the ambient seawater. The mechanisms that promote this specific, cooperative colonization are likely to require a number of bacterial and host-derived factors and activities, only some of which have been described to date. A characteristic of many host-pathogen associations is the presence of bacterial mechanisms that allow attachment to specific tissues. These mechanisms have been well characterized and often involve bacterial fimbriae or outer membrane proteins (OMPs) that act as adhesins, the expression of which has been linked to virulence regulators such as ToxR in Vibrio cholerae. Analogous or even homologous mechanisms are probably operative in the initiation and persistence of cooperative bacterial associations, although considerably less is known about them. We report the presence in V. fischeri of ompU, a gene encoding a 32.5-kDa protein homolog of two other OMPs, OmpU of V. cholerae (50.8% amino acid sequence identity) and OmpL of Photobacterium profundum (45.5% identity). A null mutation introduced into the V. fischeri ompU resulted in the loss of an OMP with an estimated molecular mass of about 34 kDa; genetic complementation of the mutant strain with a DNA fragment containing only the ompU gene restored the production of this protein. The expression of the V. fischeri OmpU was not significantly affected by either (i) iron or phosphate limitation or (ii) a mutation that renders V. fischeri defective in the synthesis of a homolog of the OMP-regulatory protein ToxR. The ompU mutant grew normally in complex nutrient media but was more susceptible to growth inhibition in the presence of either anionic detergents or the antimicrobial peptide protamine sulfate. Interestingly, colonization experiments showed that the ompU null mutant initiated a symbiotic association with juvenile light organ tissue with only about 60% of the effectiveness of the parent strain. When colonization did occur, it proceeded more slowly and resulted in an approximately fourfold-smaller bacterial population. Surprisingly, there was no evidence that in a mixed infection with its parent, the ompU-defective strain had a competitive disadvantage, suggesting that the presence of the parent strain provided a shared compensatory activity. Thus, the OmpU protein appears to play a role in the normal process by which V. fischeri initiates its colonization of the nascent light organ of juvenile squids.},
}
@article {pmid11343128,
year = {2001},
author = {Timmins, GS and Jackson, SK and Swartz, HM},
title = {The evolution of bioluminescent oxygen consumption as an ancient oxygen detoxification mechanism.},
journal = {Journal of molecular evolution},
volume = {52},
number = {4},
pages = {321-332},
doi = {10.1007/s002390010162},
pmid = {11343128},
issn = {0022-2844},
support = {P41 RR11602/RR/NCRR NIH HHS/United States ; R01 GM34250/GM/NIGMS NIH HHS/United States ; },
mesh = {Adaptation, Physiological ; Animals ; Antioxidants/*metabolism ; Biological Evolution ; Decapodiformes/physiology ; Inactivation, Metabolic/physiology ; Luminescent Measurements ; Oxygen/*metabolism/physiology/*poisoning ; Oxygen Consumption/*physiology ; Vibrio/physiology ; },
abstract = {Endogenous reductants such as hydrogen sulfide and alkylthiols provided free radical scavenging systems during the early evolution of life. The development of oxygenic photosynthesis spectacularly increased oxygen levels, and ancient life forms were obliged to develop additional antioxidative systems. We develop here the hypothesis of how "prototypical" bioluminescent reactions had a plausible role as an ancient defense against oxygen toxicity through their "futile" consumption of oxygen. As oxygen concentrations increased, sufficient light would have been emitted from such systems for detection by primitive photosensors, and evolutionary pressures could then act upon the light emitting characteristics of such systems independently of their use as futile consumers of oxygen. Finally, an example of survival of this ancient mechanism in present-day bioluminescent bacteria (in the Euprymna scolopes-Vibrio fischeri mutualism) is discussed. Once increasing ambient oxygen levels reached sufficiently high levels, the use of "futile" oxygen consumption became too bioenergetically costly, so that from this time the evolution of bioluminescence via this role was made impossible, and other mechanisms must be developed to account for the evolution of bioluminescence by a wide range of organisms that patently occurred after this (e.g., by insects).},
}
@article {pmid11321532,
year = {2001},
author = {Barbieri, E and Paster, BJ and Hughes, D and Zurek, L and Moser, DP and Teske, A and Sogin, ML},
title = {Phylogenetic characterization of epibiotic bacteria in the accessory nidamental gland and egg capsules of the squid Loligo pealei (Cephalopoda:Loliginidae).},
journal = {Environmental microbiology},
volume = {3},
number = {3},
pages = {151-167},
pmid = {11321532},
issn = {1462-2912},
mesh = {Anaerobiosis ; Animals ; Bacteria/*classification/genetics/*isolation & purification ; DNA, Bacterial/analysis/genetics ; DNA, Ribosomal/genetics ; Decapodiformes/*anatomy & histology/*microbiology ; Ecosystem ; Exocrine Glands/*microbiology ; Female ; Molecular Sequence Data ; Phylogeny ; Polymerase Chain Reaction ; Proteobacteria/*classification/genetics/*isolation & purification/physiology ; RNA, Ribosomal, 16S/genetics ; Reproduction ; Sequence Analysis, DNA ; Vibrio/classification/genetics/isolation & purification ; },
abstract = {Sexually mature female squid Loligo pealei harbour dense bacterial communities in their accessory nidamental glands (ANGs) and in their egg capsules (ECs). This study describes a molecular approach using the 16S rRNA gene (rDNA) to identify bacterial populations within the ANG and the ECs of the North Atlantic squid species L. pealei. Fluorescent in situ hybridization (FISH) and 16S rDNA analysis showed that predominantly alpha- and, to a lesser extent, gamma-proteobacteria were the predominant components of the ANG and EC bacterial communities. Sequencing results showed the presence of alpha-proteobacterial populations affiliated with the Roseobacter group and additional deep-branching alpha-proteobacterial lineages. In contrast, isolates from the ANG and ECs contained only a few alpha-proteobacteria of the Roseobacter group compared with several gamma-proteobacterial isolates, mostly Shewanella and Pseudoalteromonas species. Most of the ANG-associated bacterial populations were also found within the ECs of L. pealei. The molecular approach allowed the visualization of alpha-proteobacteria as major constituents of a bacterial symbiosis within the reproductive system of the Loliginidae.},
}
@article {pmid11234928,
year = {2000},
author = {Proctor, LM and Gunsalus, RP},
title = {Anaerobic respiratory growth of Vibrio harveyi, Vibrio fischeri and Photobacterium leiognathi with trimethylamine N-oxide, nitrate and fumarate: ecological implications.},
journal = {Environmental microbiology},
volume = {2},
number = {4},
pages = {399-406},
pmid = {11234928},
issn = {1462-2912},
mesh = {Anaerobiosis ; Animals ; Cell Respiration ; Decapodiformes/microbiology ; Dimethyl Sulfoxide/metabolism ; Ecosystem ; Fishes/microbiology ; Fumarates/*metabolism ; Methylamines/*metabolism ; Nitrate Reductases/metabolism ; Nitrates/*metabolism ; Oxidoreductases/metabolism ; *Oxidoreductases Acting on CH-CH Group Donors ; Oxidoreductases, N-Demethylating/metabolism ; Photobacterium/enzymology/*growth & development ; Substrate Specificity ; Symbiosis ; Vibrio/enzymology/*growth & development ; },
abstract = {Two symbiotic species, Photobacterium leiognathi and Vibrio fischeri, and one non-symbiotic species, Vibrio harveyi, of the Vibrionaceae were tested for their ability to grow by anaerobic respiration on various electron acceptors, including trimethylamine N-oxide (TMAO) and dimethylsulphoxide (DMSO), compounds common in the marine environment. Each species was able to grow anaerobically with TMAO, nitrate or fumarate, but not with DMSO, as an electron acceptor. Cell growth under microaerophilic growth conditions resulted in elevated levels of TMAO reductase, nitrate reductase and fumarate reductase activity in each strain, whereas growth in the presence of the respective substrate for each enzyme further elevated enzyme activity. TMAO reductase specific activity was the highest of all the reductases. Interestingly, the bacteria-colonized light organs from the two squids, Euprymna scolopes and Euprymna morsei, and the light organ of the ponyfish, Leiognathus equus, also had high levels of TMAO reductase enzyme activity, in contrast to non-symbiotic tissues. The ability of these bacterial symbionts to support cell growth by respiration with TMAO may conceivably eliminate the competition for oxygen needed for both bioluminescence and metabolism.},
}
@article {pmid11208780,
year = {2001},
author = {Visick, KL and Skoufos, LM},
title = {Two-component sensor required for normal symbiotic colonization of euprymna scolopes by Vibrio fischeri.},
journal = {Journal of bacteriology},
volume = {183},
number = {3},
pages = {835-842},
doi = {10.1128/JB.183.3.835-842.2001},
pmid = {11208780},
issn = {0021-9193},
support = {R01 GM059690/GM/NIGMS NIH HHS/United States ; 1 RO1 GM59690-01A1/GM/NIGMS NIH HHS/United States ; },
mesh = {Amino Acid Sequence ; Animals ; *Bacterial Proteins ; Base Sequence ; Decapodiformes/*microbiology ; Genes, Bacterial ; *Genes, Regulator ; Genetic Complementation Test ; Membrane Proteins/*genetics ; Molecular Sequence Data ; Mutagenesis, Insertional ; Periplasm ; Promoter Regions, Genetic ; Protein Conformation ; *Symbiosis ; Vibrio/*growth & development ; },
abstract = {The light organ of the squid Euprymna scolopes is specifically colonized to a high density by the marine bacterium Vibrio fischeri. To date, only a few factors contributing to the specificity of this symbiosis have been identified. Using a genetic screen for random transposon mutants defective in initiating the symbiotic association or in colonizing the light organ to high density, we identified a mutant of V. fischeri that exhibited an apparent defect in symbiosis initiation. This mutant was not defective in motility, luminescence, or growth in minimal medium, suggesting that it lacks an essential, previously unidentified symbiotic function. By sequence analysis, we showed that the locus inactivated in this mutant encodes a predicted 927-amino-acid protein with a high degree of similarity to the sensor component of hybrid two-component regulatory systems. We have therefore designated this locus rscS, for regulator of symbiotic colonization-sensor. Sequence analysis revealed two hydrophobic regions which may result in the formation of a periplasmic loop involved in signal recognition; PhoA fusion data supported this proposed membrane topology. We have investigated the start site of rscS transcription by primer extension and identified a putative promoter region. We hypothesize that RscS recognizes a signal associated with the light organ environment and responds by stimulating a putative response regulator that controls protein function or gene expression to coordinate early colonization events. Further studies on RscS, its cognate response regulator, and the signaling conditions will provide important insight into the interaction between V. fischeri and E. scolopes.},
}
@article {pmid11121780,
year = {2000},
author = {McFall-Ngai, MJ and Ruby, EG},
title = {Developmental biology in marine invertebrate symbioses.},
journal = {Current opinion in microbiology},
volume = {3},
number = {6},
pages = {603-607},
pmid = {11121780},
issn = {1369-5274},
support = {RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Decapodiformes/*microbiology ; Luminescent Measurements ; Species Specificity ; Symbiosis/*physiology ; Vibrio/*physiology ; },
abstract = {Associations between marine invertebrates and their cooperative bacterial symbionts offer access to an understanding of the roots of host-microbe interaction; for example, several symbioses like the squid-vibrio light organ association serve as models for investigating how each partner affects the developmental biology of the other. Previous results have identified a program of specific developmental events that unfolds as the association is initiated. In the past year, published studies have focused primarily on describing the mechanisms underlying the signaling processes that occur between the juvenile squid and the luminous bacteria that colonize it.},
}
@article {pmid11114931,
year = {2001},
author = {Stabb, EV and Reich, KA and Ruby, EG},
title = {Vibrio fischeri genes hvnA and hvnB encode secreted NAD(+)-glycohydrolases.},
journal = {Journal of bacteriology},
volume = {183},
number = {1},
pages = {309-317},
doi = {10.1128/JB.183.1.309-317.2001},
pmid = {11114931},
issn = {0021-9193},
support = {F32 GM020041/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; GM20041/GM/NIGMS NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {ADP Ribose Transferases ; Amino Acid Sequence ; Animals ; *Bacterial Proteins ; Cloning, Molecular ; Decapodiformes/anatomy & histology/*microbiology ; Gene Deletion ; Genes, Bacterial ; Molecular Sequence Data ; NAD+ Nucleosidase/chemistry/*genetics/metabolism/*secretion ; Pentosyltransferases/chemistry/*genetics/metabolism ; Poly(ADP-ribose) Polymerases/metabolism ; Sequence Alignment ; Sequence Analysis, DNA ; Symbiosis ; Vibrio/*enzymology/*genetics ; },
abstract = {HvnA and HvnB are proteins secreted by Vibrio fischeri ES114, an extracellular light organ symbiont of the squid Euprymna scolopes, that catalyze the transfer of ADP-ribose from NAD(+) to polyarginine. Based on this activity, HvnA and HvnB were presumptively designated mono-ADP-ribosyltransferases (ARTases), and it was hypothesized that they mediate bacterium-host signaling. We have cloned hvnA and hvnB from strain ES114. hvnA appears to be expressed as part of a four-gene operon, whereas hvnB is monocistronic. The predicted HvnA and HvnB amino acid sequences are 46% identical to one another and share 44% and 34% identity, respectively, with an open reading frame present in the Pseudomonas aeruginosa genome. Four lines of evidence indicate that HvnA and HvnB mediate polyarginine ADP-ribosylation not by ARTase activity, but indirectly through an NAD(+)-glycohydrolase (NADase) activity that releases free, reactive, ADP-ribose: (i) like other NADases, and in contrast to the ARTase cholera toxin, HvnA and HvnB catalyzed ribosylation of not only polyarginine but also polylysine and polyhistidine, and ribosylation was inhibited by hydroxylamine; (ii) HvnA and HvnB cleaved 1, N(6)-etheno-NAD(+) and NAD(+); (iii) incubation of HvnA and HvnB with [(32)P]NAD(+) resulted in the production of ADP-ribose; and (iv) purified HvnA displayed an NADase V(max) of 400 mol min(-1) mol(-1), which is within the range reported for other NADases and 10(2)- to 10(4)-fold higher than the minor NADase activity reported in bacterial ARTase toxins. Construction and analysis of an hvnA hvnB mutant revealed no other NADase activity in culture supernatants of V. fischeri, and this mutant initiated the light organ symbiosis and triggered regression of the light organ ciliated epithelium in a manner similar to that for the wild type.},
}
@article {pmid11038222,
year = {2000},
author = {Hirsch, AM and McFall-Ngai, MJ},
title = {Fundamental Concepts in Symbiotic Interactions: Light and Dark, Day and Night, Squid and Legume.},
journal = {Journal of plant growth regulation},
volume = {19},
number = {2},
pages = {113-130},
pmid = {11038222},
issn = {0721-7595},
abstract = {The legume-Rhizobium symbiosis and that between Euprymna scolopes and Vibrio fischeri show some surprising physiological similarities as well as differences. Both interactions rely on exchange of signal molecules, some of which are derived from bacterial cell surface molecules. Although the legume-Rhizobium symbiosis is nutritionally based as are many animal-microbe symbioses, it is not obligate because the plant initiates nodule formation only when the soil is deficient in nitrogen. In contrast, the squid-Vibrio symbiosis is obligate for the squid but is not nutritionally based. Rather, the bacteria produce light, which enables the animal to evade predators. These similarities and differences are described and discussed in term of the overall question of whether or not these two symbiotic relationships have evolved from commensal or pathogenic/parasitic interactions between prokaryotes and eukaryotes.},
}
@article {pmid11023684,
year = {2000},
author = {Foster, JS and Apicella, MA and McFall-Ngai, MJ},
title = {Vibrio fischeri lipopolysaccharide induces developmental apoptosis, but not complete morphogenesis, of the Euprymna scolopes symbiotic light organ.},
journal = {Developmental biology},
volume = {226},
number = {2},
pages = {242-254},
doi = {10.1006/dbio.2000.9868},
pmid = {11023684},
issn = {0012-1606},
support = {AI24616/AI/NIAID NIH HHS/United States ; R01RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animal Structures/*drug effects/growth & development/microbiology/ultrastructure ; Animals ; Apoptosis/*drug effects ; Decapodiformes/anatomy & histology/*growth & development/microbiology ; Epithelial Cells/drug effects ; Escherichia coli/chemistry ; Haemophilus influenzae/chemistry/genetics ; Lipid A/biosynthesis/pharmacology ; Lipopolysaccharides/isolation & purification/*pharmacology ; *Luminescent Measurements ; Microscopy, Electron, Scanning ; Morphogenesis/drug effects ; Shigella flexneri/chemistry ; Species Specificity ; *Symbiosis ; Vibrio/chemistry/*physiology ; },
abstract = {During initiation of the association between the squid host Euprymna scolopes and its bacterial partner Vibrio fischeri, the bacteria induce dramatic morphogenesis of the host symbiotic organ, a portion of which involves the signaling of widespread apoptosis of the cells in a superficial ciliated epithelium on the colonized organ. In this study, we investigated the role in this process of lipopolysaccharide (LPS), a bacterial cell-surface molecule implicated in the induction of animal cell apoptosis in other systems. Purified V. fischeri LPS, as well as the LPS of V. cholerae, Haemophilus influenzae, Escherichia coli, and Shigella flexneri, added in the concentration range of pg/ml to ng/ml, induced apoptosis in epithelial cells 10- to 100-fold above background levels. The absence of species specificity suggested that the conserved lipid A portion of the LPS was the responsible component of the LPS molecule. Lipid A from V. fischeri, E. coli, or S. flexneri induced apoptosis. In addition, strains of H. influenzae carrying a mutation in the htrB gene, which is involved in the synthesis of virulent lipid A, showed a diminished ability to induce apoptosis of host cells. Confocal microscopy using fluorescently labeled LPS indicated that the LPS behaves similar to intact bacterial symbionts, interacting with host cells in the internal crypt spaces and not directly with the superficial epithelium. Although LPS was able to induce apoptosis, it did not induce the full morphogenesis of the ciliated surface, suggesting that multiple signals are necessary to mediate the development of this animal-bacterial mutualism.},
}
@article {pmid10989339,
year = {2000},
author = {McFall-Ngai, MJ},
title = {Negotiations between animals and bacteria: the 'diplomacy' of the squid-vibrio symbiosis.},
journal = {Comparative biochemistry and physiology. Part A, Molecular & integrative physiology},
volume = {126},
number = {4},
pages = {471-480},
pmid = {10989339},
issn = {1095-6433},
mesh = {Animals ; Decapodiformes/*microbiology ; Symbiosis/*physiology ; Vibrio/*physiology ; },
abstract = {A shared characteristic among animals is their propensity to form stable, beneficial relationships with prokaryotes. Usually these associations occur in the form of consortia, i.e. a diverse assemblage of bacteria interacting with a single animal host. These complex communities, while common, have been difficult to characterize. The two-partner symbiosis between the squid Euprymna scolopes and the marine luminous bacterium Vibrio fischeri offers the opportunity to study the interaction between animal and bacterial cells, because both partners can be cultured in the laboratory and the symbiosis can be manipulated experimentally. This system is being used to characterize the mechanisms by which animals establish, develop and maintain stable alliances with bacteria. This review summarizes the progress to date on the development of this model.},
}
@article {pmid10966433,
year = {2000},
author = {Doino Lemus, J and McFall-Ngai, MJ},
title = {Alterations in the proteome of the Euprymna scolopes light organ in response to symbiotic Vibrio fischeri.},
journal = {Applied and environmental microbiology},
volume = {66},
number = {9},
pages = {4091-4097},
pmid = {10966433},
issn = {0099-2240},
support = {R01 RR012294/RR/NCRR NIH HHS/United States ; R01RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animal Structures/growth & development/metabolism/microbiology ; Animals ; Decapodiformes/growth & development/*microbiology/*physiology ; Electrophoresis, Gel, Two-Dimensional ; Light ; Proteome/*metabolism ; *Symbiosis ; Vibrio/*physiology ; },
abstract = {During the onset of the cooperative association between the Hawaiian sepiolid squid Euprymna scolopes and the marine luminous bacterium Vibrio fischeri, the anatomy and morphology of the host's symbiotic organ undergo dramatic changes that require interaction with the bacteria. This morphogenetic process involves an array of tissues, including those in direct contact with, as well as those remote from, the symbiotic bacteria. The bacteria induce the developmental program soon after colonization of the organ, although complete morphogenesis requires 96 h. In this study, to determine critical time points, we examined the biochemistry underlying bacterium-induced host development using two-dimensional polyacrylamide gel electrophoresis. Specifically, V. fischeri-induced changes in the soluble proteome of the symbiotic organ during the first 96 h of symbiosis were identified by comparing the protein profiles of symbiont-colonized and uncolonized organs. Both symbiosis-related changes and age-related changes were analyzed to determine what proportion of the differences in the proteomes was the result of specific responses to interaction with bacteria. Although no differences were detected over the first 24 h, numerous symbiosis-related changes became apparent at 48 and 96 h and were more abundant than age-related changes. In addition, many age-related protein changes occurred 48 h sooner in symbiotic animals, suggesting that the interaction of squid tissue with V. fischeri cells accelerates certain developmental processes of the symbiotic organ. These data suggest that V. fischeri-induced modifications in host tissues that occur in the first 24 h of the symbiosis are independent of marked alterations in the patterns of abundant proteins but that the full 4-day morphogenetic program requires significant alteration of the host soluble proteome.},
}
@article {pmid10963683,
year = {2000},
author = {Nyholm, SV and Stabb, EV and Ruby, EG and McFall-Ngai, MJ},
title = {Establishment of an animal-bacterial association: recruiting symbiotic vibrios from the environment.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {97},
number = {18},
pages = {10231-10235},
pmid = {10963683},
issn = {0027-8424},
support = {R01 RR012294/RR/NCRR NIH HHS/United States ; R01-RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Cloning, Molecular ; Decapodiformes/*microbiology/*physiology ; Epithelium/microbiology/physiology ; Gram-Negative Bacteria/*physiology ; Gram-Positive Bacteria/*physiology ; Green Fluorescent Proteins ; Lectins ; Luminescent Proteins/analysis/genetics ; Recombinant Proteins/analysis ; Seawater/microbiology ; *Symbiosis ; Vibrio/*physiology ; },
abstract = {While most animal-bacterial symbioses are reestablished each successive generation, the mechanisms by which the host and its potential microbial partners ensure tissue colonization remain largely undescribed. We used the model association between the squid Euprymna scolopes and Vibrio fischeri to examine this process. This light organ symbiosis is initiated when V. fischeri cells present in the surrounding seawater enter pores on the surface of the nascent organ and colonize deep epithelia-lined crypts. We discovered that when newly hatched squid were experimentally exposed to natural seawater, the animals responded by secreting a viscous material from the pores of the organ. Animals maintained in filtered seawater produced no secretions unless Gram-negative bacteria, either living or dead, were reintroduced. The viscous material bound only lectins that are specific for either N-acetylneuraminic acid or N-acetylgalactosamine, suggesting that it was composed of a mucus-containing matrix. Complex ciliated fields on the surface of the organ produced water currents that focused the matrix into a mass that was tethered to, and suspended above, the light organ pores. When V. fischeri cells were introduced into the seawater surrounding the squid, the bacteria were drawn into its fluid-filled body cavity during ventilation and were captured in the matrix. After residing as an aggregate for several hours, the symbionts migrated into the pores and colonized the crypt epithelia. This mode of infection may be an example of a widespread strategy by which aquatic hosts increase the likelihood of successful colonization by rarely encountered symbionts.},
}
@article {pmid10941780,
year = {1999},
author = {Ruby, EG},
title = {The Euprymna scolopes-Vibrio fischeri symbiosis: a biomedical model for the study of bacterial colonization of animal tissue.},
journal = {Journal of molecular microbiology and biotechnology},
volume = {1},
number = {1},
pages = {13-21},
pmid = {10941780},
issn = {1464-1801},
support = {R01-RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Decapodiformes/immunology/metabolism/*microbiology ; Humans ; Models, Biological ; Phagocytosis/immunology ; Reactive Oxygen Species/metabolism ; *Symbiosis ; Vibrio/*growth & development/immunology/metabolism ; },
abstract = {The diversity of microorganisms found in the marine environment reflects the immense size, range of physical conditions and energy sources, and evolutionary age of the sea. Because associations with living animal tissue are an important and ancient part of the ecology of many microorganisms, it is not surprising that the study of marine symbioses (including both cooperative and pathogenic interactions) has produced numerous discoveries of biotechnological and biomedical significance. The association between the bioluminescent bacterium Vibrio fischeri and the sepiolid squid Euprymna scolopes has emerged as a productive model system for the investigation of the mechanisms by which cooperative bacteria initiate colonization of specific host tissues. The results of the last decade of research on this system have begun to reveal surprising similarities between this association and the pathogenic associations of disease-causing Vibrio species, including those of interest to human health and aquaculture. Studies of the biochemical and molecular events underlying the development of the squid-vibrio symbiosis can be expected to continue to increase our understanding of the factors controlling both benign and pathogenic bacterial associations.},
}
@article {pmid10931314,
year = {2000},
author = {Graf, J and Ruby, EG},
title = {Novel effects of a transposon insertion in the Vibrio fischeri glnD gene: defects in iron uptake and symbiotic persistence in addition to nitrogen utilization.},
journal = {Molecular microbiology},
volume = {37},
number = {1},
pages = {168-179},
pmid = {10931314},
issn = {0950-382X},
support = {RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Carbon/metabolism ; Cloning, Molecular ; *DNA Transposable Elements ; Decapodiformes/microbiology ; Genetic Complementation Test ; Iron/*metabolism ; Nitrogen/*metabolism ; Nucleotidyltransferases/*genetics/metabolism ; PII Nitrogen Regulatory Proteins ; Phenotype ; Siderophores/metabolism ; *Symbiosis ; Vibrio/classification/*enzymology/genetics/growth & development ; },
abstract = {Vibrio fischeri is the sole species colonizing the light-emitting organ of the Hawaiian squid, Euprymna scolopes. Upon entering the nascent light organ of a newly hatched juvenile squid, the bacteria undergo morphological and physiological changes that include the loss of flagellation and the induction of bioluminescence. These and other events reveal a pattern of genetic regulation that is a response to the colonization of host tissue. In this study, we isolated and characterized a glnD:mTn5Cm mutant of V. fischeri. In addition to the predicted defects in the efficiency of nitrogen utilization, this glnD mutant had an unexpected reduction in the ability to produce siderophore and grow under iron-limiting conditions. Although the glnD mutant could colonize juvenile squid normally over the first 24 h, it was subsequently unable to persist in the light organ to the usual extent. This persistence phenotype was more severe if the mutant was pregrown under iron-limiting conditions before inoculation, but could be ameliorated by the presence of excess iron. These results indicate that the ability to respond to iron limitation may be an important requirement in the developing symbiosis. Supplying the glnD gene in trans restored normal efficiency of nitrogen use, iron sequestration and colonization phenotypes to the glnD:mTn5Cm mutant; thus, there appears to be a genetic and/or metabolic linkage between nitrogen sensing, siderophore synthesis and symbiosis competence in V. fischeri that involves the glnD gene.},
}
@article {pmid10919820,
year = {2000},
author = {Nishiguchi, MK},
title = {Temperature affects species distribution in symbiotic populations of Vibrio spp.},
journal = {Applied and environmental microbiology},
volume = {66},
number = {8},
pages = {3550-3555},
pmid = {10919820},
issn = {0099-2240},
mesh = {Animals ; Colony Count, Microbial ; Decapodiformes/*classification/*microbiology ; Light ; Species Specificity ; *Symbiosis ; Temperature ; Vibrio/*growth & development/isolation & purification ; },
abstract = {The genus Sepiola (Cephalopoda: Sepiolidae) contains 10 known species that occur in the Mediterranean Sea today. All Sepiola species have a light organ that contains at least one of two species of luminous bacteria, Vibrio fischeri and Vibrio logei. The two Vibrio species coexist in at least four Sepiola species (S. affinis, S. intermedia, S. ligulata, and S. robusta), and their concentrations in the light organ depend on changes in certain abiotic factors, including temperature. Strains of V. fischeri grew faster in vitro and in Sepiola juveniles when they were incubated at 26 degrees C. In contrast, strains of V. logei grew faster at 18 degrees C in culture and in Sepiola juveniles. When aposymbiotic S. affinis or S. ligulata juveniles were inoculated with one Vibrio species, all strains of V. fischeri and V. logei were capable of infecting both squid species at the optimum growth temperatures, regardless of the squid host from which the bacteria were initially isolated. However, when two different strains of V. fischeri and V. logei were placed in direct competition with each other at either 18 or 26 degrees C, strains of V. fischeri were present in sepiolid light organs in greater concentrations at 26 degrees C, whereas strains of V. logei were present in greater concentrations at 18 degrees C. In addition to the competition experiments, the ratios of the two bacterial species in adult Sepiola specimens caught throughout the season at various depths differed, and these differences were correlated with the temperature in the surrounding environment. My findings contribute additional data concerning the ecological and environmental factors that affect host-symbiont recognition and may provide insight into the evolution of animal-bacterium specificity.},
}
@article {pmid10913092,
year = {2000},
author = {Visick, KL and Foster, J and Doino, J and McFall-Ngai, M and Ruby, EG},
title = {Vibrio fischeri lux genes play an important role in colonization and development of the host light organ.},
journal = {Journal of bacteriology},
volume = {182},
number = {16},
pages = {4578-4586},
pmid = {10913092},
issn = {0021-9193},
support = {F32 GM017424/GM/NIGMS NIH HHS/United States ; R01 RR012294/RR/NCRR NIH HHS/United States ; F32GM17424-02/GM/NIGMS NIH HHS/United States ; RR-12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Bacterial Proteins/genetics ; Decapodiformes/microbiology ; Electric Organ/microbiology ; Epithelial Cells/cytology/*microbiology ; Luciferases/*genetics ; Luminescent Measurements ; Mutagenesis ; *Operon ; Plasmids ; Recombination, Genetic ; Repressor Proteins/genetics ; Symbiosis ; Trans-Activators/genetics ; Vibrio/enzymology/genetics/*physiology ; },
abstract = {The bioluminescent bacterium Vibrio fischeri and juveniles of the squid Euprymna scolopes specifically recognize and respond to one another during the formation of a persistent colonization within the host's nascent light-emitting organ. The resulting fully developed light organ contains brightly luminescing bacteria and has undergone a bacterium-induced program of tissue differentiation, one component of which is a swelling of the epithelial cells that line the symbiont-containing crypts. While the luminescence (lux) genes of symbiotic V. fischeri have been shown to be highly induced within the crypts, the role of these genes in the initiation and persistence of the symbiosis has not been rigorously examined. We have constructed and examined three mutants (luxA, luxI, and luxR), defective in either luciferase enzymatic or regulatory proteins. All three are unable to induce normal luminescence levels in the host and, 2 days after initiating the association, had a three- to fourfold defect in the extent of colonization. Surprisingly, these lux mutants also were unable to induce swelling in the crypt epithelial cells. Complementing, in trans, the defect in light emission restored both normal colonization capability and induction of swelling. We hypothesize that a diminished level of oxygen consumption by a luciferase-deficient symbiotic population is responsible for the reduced fitness of lux mutants in the light organ crypts. This study is the first to show that the capacity for bioluminescence is critical for normal cell-cell interactions between a bacterium and its animal host and presents the first examples of V. fischeri genes that affect normal host tissue development.},
}
@article {pmid10831459,
year = {2000},
author = {Vuddhakul, V and Chowdhury, A and Laohaprertthisan, V and Pungrasamee, P and Patararungrong, N and Thianmontri, P and Ishibashi, M and Matsumoto, C and Nishibuchi, M},
title = {Isolation of a pandemic O3:K6 clone of a Vibrio parahaemolyticus strain from environmental and clinical sources in Thailand.},
journal = {Applied and environmental microbiology},
volume = {66},
number = {6},
pages = {2685-2689},
pmid = {10831459},
issn = {0099-2240},
mesh = {Animals ; Bacteriological Techniques ; Colony Count, Microbial ; Decapoda (Crustacea)/microbiology ; Decapodiformes/microbiology ; Diarrhea/microbiology ; *Disease Outbreaks ; Fishes/microbiology ; Humans ; Immunomagnetic Separation ; Polymerase Chain Reaction/methods ; Seafood/*microbiology ; Thailand/epidemiology ; Vibrio Infections/epidemiology/*microbiology ; Vibrio parahaemolyticus/classification/*genetics/*isolation & purification ; },
abstract = {Application of an immunomagnetic enrichment method selective for Vibrio parahaemolyticus serovar K6 allowed isolation of a strain belonging to the pandemic O3:K6 clone of V. parahaemolyticus from fresh shellfish not implicated in a clinical case in southern Thailand. Arbitrarily primed PCR profiles of this strain, clinical O3:K6 strains isolated from sporadic diarrhea cases in the same area, and a standard pandemic O3:K6 strain were indistinguishable.},
}
@article {pmid10781550,
year = {2000},
author = {Callahan, SM and Dunlap, PV},
title = {LuxR- and acyl-homoserine-lactone-controlled non-lux genes define a quorum-sensing regulon in Vibrio fischeri.},
journal = {Journal of bacteriology},
volume = {182},
number = {10},
pages = {2811-2822},
pmid = {10781550},
issn = {0021-9193},
mesh = {4-Butyrolactone/*analogs & derivatives/metabolism ; Amino Acid Sequence ; Animals ; Bacterial Proteins/*genetics/*metabolism ; Base Sequence ; DNA, Bacterial ; Decapodiformes/microbiology ; Gene Expression Regulation, Bacterial ; Intramolecular Transferases/*genetics ; Molecular Sequence Data ; *Regulon ; Repressor Proteins/genetics/*metabolism ; Symbiosis ; Trans-Activators/genetics/*metabolism ; Vibrio/*genetics ; },
abstract = {The luminescence (lux) operon (luxICDABEG) of the symbiotic bacterium Vibrio fischeri is regulated by the transcriptional activator LuxR and two acyl-homoserine lactone (acyl-HSL) autoinducers (the luxI-dependent 3-oxo-hexanoyl-HSL [3-oxo-C6-HSL] and the ainS-dependent octanoyl-HSL [C8-HSL]) in a population density-responsive manner called quorum sensing. To identify quorum-sensing-regulated (QSR) proteins different from those encoded by lux genes, we examined the protein patterns of V. fischeri quorum-sensing mutants defective in luxI, ainS, and luxR by two-dimensional polyacrylamide gel electrophoresis. Five non-Lux QSR proteins, QsrP, RibB, AcfA, QsrV, and QSR 7, were identified; their production occurred preferentially at high population density, required both LuxR and 3-oxo-C6-HSL, and was inhibited by C8-HSL at low population density. The genes encoding two of the QSR proteins were characterized: qsrP directs cells to synthesize an apparently novel periplasmic protein, and ribB is a homolog of the Escherichia coli gene for 3,4-dihydroxy-2-butanone 4-phosphate synthase, a key enzyme for riboflavin synthesis. The qsrP and ribB promoter regions each contained a sequence similar to the lux operon lux box, a 20-bp region of dyad symmetry necessary for LuxR/3-oxo-C6-HSL-dependent activation of lux operon transcription. V. fischeri qsrP and ribB mutants exhibited no distinct phenotype in culture. However, a qsrP mutant, in competition with its parent strain, was less successful in colonizing Euprymna scolopes, the symbiotic host of V. fischeri. The newly identified QSR genes, together with the lux operon, define a LuxR/acyl-HSL-responsive quorum-sensing regulon in V. fischeri.},
}
@article {pmid10714980,
year = {2000},
author = {Visick, KL and McFall-Ngai, MJ},
title = {An exclusive contract: specificity in the Vibrio fischeri-Euprymna scolopes partnership.},
journal = {Journal of bacteriology},
volume = {182},
number = {7},
pages = {1779-1787},
pmid = {10714980},
issn = {0021-9193},
support = {R01 RR10926/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Decapodiformes/cytology/growth & development/*microbiology/*physiology ; Ecosystem ; Evolution, Molecular ; *Luminescent Measurements ; Macrophages/cytology/microbiology/physiology ; Species Specificity ; Symbiosis/*physiology ; Vibrio/cytology/growth & development/*physiology ; },
}
@article {pmid10653967,
year = {2000},
author = {Claes, MF and Dunlap, PV},
title = {Aposymbiotic culture of the sepiolid squid Euprymna scolopes: role of the symbiotic bacterium Vibrio fischeri in host animal growth, development, and light organ morphogenesis.},
journal = {The Journal of experimental zoology},
volume = {286},
number = {3},
pages = {280-296},
pmid = {10653967},
issn = {0022-104X},
mesh = {Animal Structures/*growth & development ; Animals ; Behavior, Animal/physiology ; Cilia ; Decapodiformes/*embryology/microbiology ; Epithelium/growth & development ; Female ; Luminescent Measurements ; Male ; Morphogenesis ; Symbiosis/*physiology ; Vibrio/*physiology ; },
abstract = {The sepiolid squid Euprymna scolopes forms a bioluminescent mutualism with the luminous bacterium Vibrio fischeri, harboring V. fischeri cells in a complex ventral light organ and using the bacterial light in predator avoidance. To characterize the contribution of V. fischeri to the growth and development of E. scolopes and to define the long-term effects of bacterial colonization on light organ morphogenesis, we developed a mariculture system for the culture of E. scolopes from hatching to adulthood, employing artificial seawater, lighting that mimicked that of the natural environment, and provision of prey sized to match the developmental stage of E. scolopes. Animals colonized by V. fischeri and animals cultured in the absence of V. fischeri (aposymbiotic) grew and survived equally well, developed similarly, and reached sexual maturity at a similar age. Development of the light organ accessory tissues (lens, reflectors, and ink sac) was similar in colonized and aposymbiotic animals with no obvious morphometric or histological differences. Colonization by V. fischeri influenced regression of the ciliated epithelial appendages (CEAs), the long-term growth of the light organ epithelial tubules, and the appearance of the cells composing the ciliated ducts, which exhibit characteristics of secretory tissue. In certain cases, aposymbiotic animals retained the CEAs in a partially regressed state and remained competent to initiate symbiosis with V. fischeri into adulthood. In other cases, the CEAs regressed fully in aposymbiotic animals, and these animals were not colonizable. The results demonstrate that V. fischeri is not required for normal growth and development of the animal or for development of the accessory light organ tissues and that morphogenesis of only those tissues coming in contact with the bacteria (CEAs, ciliated ducts, and light organ epithelium) is altered by bacterial colonization of the light organ. Therefore, V. fischeri apparently makes no major metabolic contribution to E. scolopes beyond light production, and post-embryonic development of the light organ is essentially symbiont independent. J. Exp. Zool. 286:280-296, 2000.},
}
@article {pmid10498950,
year = {1999},
author = {Ruby, EG and McFall-Ngai, MJ},
title = {Oxygen-utilizing reactions and symbiotic colonization of the squid light organ by Vibrio fischeri.},
journal = {Trends in microbiology},
volume = {7},
number = {10},
pages = {414-420},
pmid = {10498950},
issn = {0966-842X},
support = {R01-RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Decapodiformes/*microbiology/physiology ; Light ; Oxygen/*metabolism ; *Symbiosis ; Vibrio/*growth & development ; },
abstract = {A major goal in microbiology is to understand the processes by which bacteria successfully colonize host tissue. Although a wealth of studies focusing on pathogenic microorganisms has revealed much about the rare interactions that result in disease, far less is known about the regulation of the ubiquitous, long-term, cooperative associations of bacteria with their animal hosts.},
}
@article {pmid10022605,
year = {1999},
author = {Small, AL and McFall-Ngai, MJ},
title = {Halide peroxidase in tissues that interact with bacteria in the host squid Euprymna scolopes.},
journal = {Journal of cellular biochemistry},
volume = {72},
number = {4},
pages = {445-457},
pmid = {10022605},
issn = {0730-2312},
support = {R01-RR10926-01A1/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Decapodiformes/*metabolism/microbiology ; Epithelial Cells/enzymology ; Immunohistochemistry ; Peroxidase/analysis/*metabolism ; RNA, Messenger/metabolism ; Vibrio/*chemistry ; },
abstract = {An enzyme with similarities to myeloperoxidase, the antimicrobial halide peroxidase in mammalian neutrophils, occurs abundantly in the light organ tissue of Euprymna scolopes, a squid that maintains a beneficial association with the luminous bacterium Vibrio fischeri. Using three independent assays typically applied to the analysis of halide peroxidase enzymes, we directly compared the activity of the squid enzyme with that of human myeloperoxidase. One of these methods, the diethanolamine assay, confirmed that the squid peroxidase requires halide ions for its activity. The identification of a halide peroxidase in a cooperative bacterial association suggested that this type of enzyme can function not only to control pathogens, but also to modulate the interactions of host animals with their beneficial partners. To determine whether the squid peroxidase functions under both circumstances, we examined its distribution in a variety of host tissues, including those that typically interact with bacteria and those that do not. Tissues interacting with bacteria included those that have specific cooperative associations with bacteria (i.e., the light organ and accessory nidamental gland) and those that have transient nonspecific interactions with bacteria (i.e., the gills, which clear the cephalopod circulatory system of invading microorganisms). These bacteria-associated tissues were compared with the eye, digestive gland, white body, and ink-producing tissues, which do not typically interact directly with bacteria. Peroxidase enzyme assays, immunocytochemical localization, and DNA-RNA hybridizations showed that the halide-dependent peroxidase is consistently expressed in high concentration in tissues that interact bacteria. Elevated levels of the peroxidase were also found in the ink-producing tissues, which are known to have enzymatic pathways associated with antimicrobial activity. Taken together, these data suggest that the host uses a common biochemical response to the variety of types of associations that it forms with microorganisms.},
}
@article {pmid9924775,
year = {1998},
author = {Montgomery, MK and McFall-Ngai, MJ},
title = {Late postembryonic development of the symbiotic light organ of Euprymna scolopes (Cephalopoda: Sepiolidae).},
journal = {The Biological bulletin},
volume = {195},
number = {3},
pages = {326-336},
doi = {10.2307/1543144},
pmid = {9924775},
issn = {0006-3185},
support = {R01-RR12294-02/RR/NCRR NIH HHS/United States ; RR01024/RR/NCRR NIH HHS/United States ; },
mesh = {Animal Structures/*growth & development/ultrastructure ; Animals ; Crystallins/analysis ; Decapodiformes/*growth & development ; Immunohistochemistry ; *Light ; Microscopy, Electron, Scanning ; *Symbiosis ; Time Factors ; },
abstract = {The symbiotic light organ of the sepiolid squid Euprymna scolopes undergoes significant anatomical, morphological, and biochemical changes during development. Previously we described the embryonic organogenesis and early postembryonic development of the light organ. During embryogenesis, tissues are developed that will promote the onset of an association with Vibrio fischeri, the light organ symbiont. Upon inoculation, and in response to the first interactions with the bacterial symbionts, the light organ undergoes a dramatic morphogenesis during the first 4-5 days of postembryonic development. Here we describe the final developmental stage of the light organ system, a period of late postembryonic development in which particular tissues of the light organ mature that eventually mediate the functional symbiosis. The maturation of the light organ occurs within 1 to 2 weeks posthatch and entails two principal processes: (1) changes in the shape of the organ and elaboration of the accessory tissues that modify the bacterially produced light; and (2) branching of the epithelial crypts, where the bacterial symbionts reside, and restriction of epithelial cell proliferation to the deepest branches of the crypts. The gross morphological changes of the organ occur in the absence of V. fischeri, although rudiments of the ciliated field of the hatchling remain in animals not exposed to the microbial symbiont.},
}
@article {pmid9891783,
year = {1998},
author = {Wilson, T and Hastings, JW},
title = {Bioluminescence.},
journal = {Annual review of cell and developmental biology},
volume = {14},
number = {},
pages = {197-230},
doi = {10.1146/annurev.cellbio.14.1.197},
pmid = {9891783},
issn = {1081-0706},
mesh = {Animals ; Bacteria/metabolism ; Cnidaria/metabolism ; Coleoptera ; Eukaryota/metabolism ; Firefly Luciferin/*metabolism ; Fishes ; Green Fluorescent Proteins ; Light ; Luciferases/*metabolism ; *Luminescent Measurements ; Luminescent Proteins/metabolism ; },
abstract = {Bioluminescence has evolved independently many times; thus the responsible genes are unrelated in bacteria, unicellular algae, coelenterates, beetles, fishes, and others. Chemically, all involve exergonic reactions of molecular oxygen with different substrates (luciferins) and enzymes (luciferases), resulting in photons of visible light (approximately 50 kcal). In addition to the structure of luciferan, several factors determine the color of the emissions, such as the amino acid sequence of the luciferase (as in beetles, for example) or the presence of accessory proteins, notably GFP, discovered in coelenterates and now used as a reporter of gene expression and a cellular marker. The mechanisms used to control the intensity and kinetics of luminescence, often emitted as flashes, also vary. Bioluminescence is credited with the discovery of how some bacteria, luminous or not, sense their density and regulate specific genes by chemical communication, as in the fascinating example of symbiosis between luminous bacteria and squid.},
}
@article {pmid9818359,
year = {1998},
author = {Nyholm, SV and McFall-Ngai, MJ},
title = {Sampling the light-organ microenvironment of Euprymna scolopes: description of a population of host cells in association with the bacterial symbiont Vibrio fischeri.},
journal = {The Biological bulletin},
volume = {195},
number = {2},
pages = {89-97},
doi = {10.2307/1542815},
pmid = {9818359},
issn = {0006-3185},
support = {R01 RR10926-O1A1/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Circadian Rhythm ; Colony Count, Microbial ; Decapodiformes/cytology/*microbiology/physiology ; Environment ; Fluorescent Dyes/chemistry ; Hemocytes/physiology/ultrastructure ; Hydrogen-Ion Concentration ; Light ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Microscopy, Fluorescence ; Microscopy, Phase-Contrast ; Symbiosis/*physiology ; Vibrio/physiology/*ultrastructure ; },
abstract = {The symbiosis between the squid Euprymna scolopes and the luminous bacterium Vibrio fischeri has a pronounced diel rhythm, one component of which is the venting of the contents of the light organ into the surrounding seawater each day at dawn. In this study, we explored the use of this behavior to sample the microenvironment of the light-organ crypts. Intact crypt contents, which emerge from the lateral pores of the organ as a thick paste-like exudate, were collected from anesthetized host animals that had been exposed to a light cue. Microscopy revealed that the expelled material is composed of a conspicuous population of host cells in association with the bacterial symbionts, all of which are embedded in a dense acellular matrix that strongly resembles the bacteria-based biofilms described in other systems. Assays of the viability of expelled crypt cells revealed no dead bacterial symbionts and a mixture of live and dead host cells. Analyses of the ultrastructure, biochemistry, and phagocytic activity of a subset of the host cell population suggested that some of these cells are macrophage-like molluscan hemocytes.},
}
@article {pmid9726861,
year = {1998},
author = {Nishiguchi, MK and Ruby, EG and McFall-Ngai, MJ},
title = {Competitive dominance among strains of luminous bacteria provides an unusual form of evidence for parallel evolution in Sepiolid squid-vibrio symbioses.},
journal = {Applied and environmental microbiology},
volume = {64},
number = {9},
pages = {3209-3213},
pmid = {9726861},
issn = {0099-2240},
support = {R01 RR10926/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; Biological Evolution ; DNA, Bacterial ; Decapodiformes/genetics/*microbiology ; Electron Transport Complex IV/genetics ; Glyceraldehyde-3-Phosphate Dehydrogenases/genetics ; Luminescent Measurements ; Molecular Sequence Data ; *Phylogeny ; Sequence Analysis, DNA ; Species Specificity ; *Symbiosis ; Vibrio/*genetics/*growth & development ; },
abstract = {One of the principal assumptions in symbiosis research is that associated partners have evolved in parallel. We report here experimental evidence for parallel speciation patterns among several partners of the sepiolid squid-luminous bacterial symbioses. Molecular phylogenies for 14 species of host squids were derived from sequences of both the nuclear internal transcribed spacer region and the mitochondrial cytochrome oxidase subunit I; the glyceraldehyde phosphate dehydrogenase locus was sequenced for phylogenetic determinations of 7 strains of bacterial symbionts. Comparisons of trees constructed for each of the three loci revealed a parallel phylogeny between the sepiolids and their respective symbionts. Because both the squids and their bacterial partners can be easily cultured independently in the laboratory, we were able to couple these phylogenetic analyses with experiments to examine the ability of the different symbiont strains to compete with each other during the colonization of one of the host species. Our results not only indicate a pronounced dominance of native symbiont strains over nonnative strains, but also reveal a hierarchy of symbiont competency that reflects the phylogenetic relationships of the partners. For the first time, molecular systematics has been coupled with experimental colonization assays to provide evidence for the existence of parallel speciation among a set of animal-bacterial associations.},
}
@article {pmid9716720,
year = {1998},
author = {Foster, JS and McFall-Ngai, MJ},
title = {Induction of apoptosis by cooperative bacteria in the morphogenesis of host epithelial tissues.},
journal = {Development genes and evolution},
volume = {208},
number = {6},
pages = {295-303},
pmid = {9716720},
issn = {0949-944X},
support = {R01-RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Animals ; *Apoptosis ; Decapodiformes/*microbiology ; Endonucleases/metabolism ; Epithelium/anatomy & histology ; In Situ Nick-End Labeling ; Microscopy, Electron, Scanning ; Vibrio/enzymology/*physiology ; },
abstract = {Associations with pathogenic bacteria have recently been shown to initiate apoptotic programs in the cells of their animal hosts, where host cell death is hypothesized to be a response of the immune system, either initiated as a mechanism of host defense or bacterial offense. In this study, we present evidence that bacterial initiation of apoptosis is neither restricted to pathogenesis nor to the initation of an immune response. In the cooperative association between the sepiolid squid Euprymna scolopes and the luminous bacterium Vibrio fischeri, the bacteria induce a dramatic morphogenesis of the host tissues during the first few days of interaction between these partners. The most striking change is the bacteria-triggered loss of an extensive superficial epithelium that potentiates the infection process. Our analyses of these tissues revealed that the bacteria induce apoptosis in the cells that comprise this epithelium within hours of the interaction with bacteria. Ultrastructural analysis revealed that after 24 h the integrity of the epithelium had been lost, i.e., the basement membrane had degenerated and the majority of the cells exhibited signs of apoptosis, most notably chromatin condensation. Analysis of these tissues with probes that reveal intracellular acidification showed that the cells first undergo an initial acidification beginning about 6-8 h after exposure to V. fischeri. As determined by end-labeling of DNA fragments, extensive endonuclease activity was detected at approximately 16-20 h post-infection. These data provide evidence that cooperative bacteria can participate in the remodeling of host tissues through the induction of host apoptotic programs.},
}
@article {pmid9619105,
year = {1998},
author = {Hooper, LV and Bry, L and Falk, PG and Gordon, JI},
title = {Host-microbial symbiosis in the mammalian intestine: exploring an internal ecosystem.},
journal = {BioEssays : news and reviews in molecular, cellular and developmental biology},
volume = {20},
number = {4},
pages = {336-343},
doi = {10.1002/(SICI)1521-1878(199804)20:4<336::AID-BIES10>3.0.CO;2-3},
pmid = {9619105},
issn = {0265-9247},
mesh = {Adaptation, Physiological ; Animals ; Decapodiformes/microbiology ; Fabaceae/microbiology ; Germ-Free Life ; Humans ; Intestines/*microbiology ; Luminescent Measurements ; Mammals/*microbiology ; Mice ; Models, Biological ; Plants, Medicinal ; Rhizobium/physiology ; Symbiosis/*physiology ; Vibrio/physiology ; },
abstract = {The mammalian intestine contains a complex, dynamic, and spatially diversified society of nonpathogenic bacteria. Very little is known about the factors that help establish host-microbial symbiosis in this open ecosystem. By introducing single genetically manipulatable components of the microflora into germfree mice, simplified model systems have been created that will allow conversations between host and microbe to be heard and understood. Other paradigms of host-microbial symbiosis suggest that these interactions will involve an exchange of biochemical signals between host and symbionts as well as among the bacteria themselves. The integration of molecular microbiology, cell biology, and gnotobiology should provide new insights about how we adapt to a microbial world and reveal the roles played by our indigenous, 'nonpathogenic' flora.},
}
@article {pmid9555890,
year = {1998},
author = {Visick, KL and Ruby, EG},
title = {The periplasmic, group III catalase of Vibrio fischeri is required for normal symbiotic competence and is induced both by oxidative stress and by approach to stationary phase.},
journal = {Journal of bacteriology},
volume = {180},
number = {8},
pages = {2087-2092},
pmid = {9555890},
issn = {0021-9193},
support = {F32 GM017424/GM/NIGMS NIH HHS/United States ; 1F32GM174724-01A1/GM/NIGMS NIH HHS/United States ; },
mesh = {Animals ; Base Sequence ; Catalase/*biosynthesis/genetics ; Decapodiformes/microbiology ; Enzyme Induction ; Escherichia coli/enzymology ; Gene Expression Regulation, Bacterial ; *Genes, Bacterial ; Kinetics ; Luminescent Measurements ; Molecular Sequence Data ; *Oxidative Stress ; Photoreceptor Cells/microbiology ; Plasmids ; Recombinant Proteins/biosynthesis ; Restriction Mapping ; Symbiosis ; Vibrio/genetics/growth & development/*physiology ; },
abstract = {The catalase gene, katA, of the sepiolid squid symbiont Vibrio fischeri has been cloned and sequenced. The predicted amino acid sequence of KatA has a high degree of similarity to the recently defined group III catalases, including those found in Haemophilus influenzae, Bacteroides fragilis, and Proteus mirabilis. Upstream of the predicted start codon of katA is a sequence that closely matches the consensus sequence for promoters regulated in Escherichia coli by the alternative sigma factor encoded by rpoS. Further, the level of expression of the cloned katA gene in an E. coli rpoS mutant is much lower than in wild-type E. coli. Catalase activity is induced three- to fourfold both as growing V. fischeri cells approach stationary phase and upon the addition of a small amount of hydrogen peroxide during logarithmic growth. The catalase activity was localized in the periplasm of wild-type V. fischeri cells, where its role could be to detoxify hydrogen peroxide coming from the external environment. No significant catalase activity could be detected in a katA null mutant strain, demonstrating that KatA is the predominately expressed catalase in V. fischeri and indicating that V. fischeri carries only a single catalase gene. The catalase mutant was defective in its ability to competitively colonize the light organs of juvenile squids in coinoculation experiments with the parent strain, suggesting that the catalase enzyme plays an important role in the symbiosis between V. fischeri and its squid host.},
}
@article {pmid9465100,
year = {1998},
author = {Graf, J and Ruby, EG},
title = {Host-derived amino acids support the proliferation of symbiotic bacteria.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {95},
number = {4},
pages = {1818-1822},
pmid = {9465100},
issn = {0027-8424},
mesh = {Amino Acids/*metabolism ; Animals ; Decapodiformes/microbiology ; Luminescent Measurements ; Microscopy, Electron ; Mutagenesis ; *Symbiosis ; Vibrio/*physiology ; },
abstract = {Animals are typically colonized by diverse bacterial symbionts, many of which are commensal and, in numerous cases, even essential for their host's proper development and growth. In exchange, the host must supply a sufficient array and quantity of nutrients to support the proliferation and persistence of its microbial community. In this investigation, we have examined such a nutritional environment by determining the symbiotic competence of auxotrophic mutants of the bioluminescent bacterium Vibrio fischeri, and have demonstrated that the host squid Euprymna scolopes provides at least 9 aa to the growing culture of symbiotic V. fischeri present in its light-emitting organ. We also collected and analyzed the extracellular fluid from this organ, in which the symbionts reside, and confirmed that it contained significant amounts of amino acids. The combined results suggested that host-derived free amino acids, as well as peptides or proteins, are a source of the amino acids that support the growth of the symbionts. This work describes a technique to sample the symbionts and their surrounding environment without contamination by host tissue components and, in combination with molecular genetic studies, allows the characterization of the nutritional conditions that support a cooperative animal-bacterial symbiosis.},
}
@article {pmid9453641,
year = {1998},
author = {Lamarcq, LH and McFall-Ngai, MJ},
title = {Induction of a gradual, reversible morphogenesis of its host's epithelial brush border by Vibrio fischeri.},
journal = {Infection and immunity},
volume = {66},
number = {2},
pages = {777-785},
pmid = {9453641},
issn = {0019-9567},
mesh = {Actins/analysis/genetics ; Animals ; Decapodiformes ; Epithelium/ultrastructure ; In Situ Hybridization ; Microvilli/physiology/*ultrastructure ; Morphogenesis ; RNA, Messenger/analysis ; Symbiosis ; Vibrio/*physiology ; },
abstract = {Bacteria exert a variety of influences on the morphology and physiology of animal cells whether they are pathogens or cooperative partners. The association between the luminous bacterium Vibrio fischeri and the sepiolid squid Euprymna scolopes provides an experimental model for the study of the influence of extracellular bacteria on the development of host epithelia. In this study, we analyzed bacterium-induced changes in the brush borders of the light organ crypt epithelia during the initial hours following colonization of this tissue. Transmission electron microscopy of the brush border morphology in colonized and uncolonized hosts revealed that the bacteria effect a fourfold increase in microvillar density over the first 4 days of the association. Estimates of the proportions of bacterial cells in contact with host microvilli showed that the intimacy of the bacterial cells with animal cell surfaces increases significantly during this time. Antibiotic curing of the organ following colonization showed that sustained interaction with bacteria is essential for the retention of the induced morphological changes. Bacteria that are defective in either light production or colonization efficiency produced changes similar to those by the parent strain. Conventional fluorescence and confocal scanning laser microscopy revealed that the brush border is supported by abundant filamentous actin. However, in situ hybridization with beta-actin probes did not show marked bacterium-induced increases in beta-actin gene expression. These experiments demonstrate that the E. scolopes-V. fischeri system is a viable model for the experimental study of bacterium-induced changes in host brush border morphology.},
}
@article {pmid28574783,
year = {1998},
author = {Kaufman, MR and Ikeda, Y and Patton, C and van Dykhuizen, G and Epel, D},
title = {Bacterial Symbionts Colonize the Accessory Nidamental Gland of the Squid Loligo opalescens via Horizontal Transmission.},
journal = {The Biological bulletin},
volume = {194},
number = {1},
pages = {36-43},
doi = {10.2307/1542511},
pmid = {28574783},
issn = {1939-8697},
abstract = {The accessory nidamental gland (AN gland), a reproductive organ of the mature female squid Loligo opalescens, harbors a dense culture of bacteria of unknown function. A multilayered sheath surrounding the L. opalescens egg case is similarly colonized by bacteria that presumably originate in the AN gland, as evidenced by their presence in the egg case at oviposition. This study investigates how these bacteria are transmitted to juvenile squid and examines some morphological consequences of bacterial colonization of AN gland tissues. By observing the structure of the AN gland in adults and the development and bacterial colonization of the gland in juveniles raised in captivity, we determined that the AN gland was absent in newly hatched squid and did not appear until 87 days post-hatching. At 129 days posthatching, the organ displayed tubules composed of a single layer of epithelial cells and expressing numerous cilia and microvilli. These tubules were not yet fully formed and thus were open to the mantle cavity and external seawater, possibly to aid in the acquisition of microorganisms. Since the AN gland developed a considerable time after hatching, it most likely acquires its symbionts horizontally from environmental seawater and not vertically from the egg case sheath. The switch from expression of cilia to production of microvilli on the epithelial cell surface may dictate the competence of the tissue for bacterial colonization. Electron microscopic examination of juvenile and adult AN glands revealed that an analogous process occurs during the development of the related light organ of other cephalopod species that harbor symbiotic bacteria.},
}
@article {pmid9422593,
year = {1998},
author = {Fidopiastis, PM and von Boletzky, S and Ruby, EG},
title = {A new niche for Vibrio logei, the predominant light organ symbiont of squids in the genus Sepiola.},
journal = {Journal of bacteriology},
volume = {180},
number = {1},
pages = {59-64},
pmid = {9422593},
issn = {0021-9193},
support = {R01 RR012294/RR/NCRR NIH HHS/United States ; RR12294/RR/NCRR NIH HHS/United States ; },
mesh = {Aldehydes/pharmacology ; Animals ; Biological Evolution ; Colony Count, Microbial ; DNA, Ribosomal/genetics ; Decapodiformes/*microbiology ; *Luminescent Measurements ; Polymerase Chain Reaction/methods ; RNA, Bacterial/genetics ; RNA, Ribosomal, 16S/genetics ; Sequence Homology, Nucleic Acid ; Symbiosis/*physiology ; Temperature ; Vibrio/genetics/*growth & development/pathogenicity ; },
abstract = {Two genera of sepiolid squids--Euprymna, found primarily in shallow, coastal waters of Hawaii and the Western Pacific, and Sepiola, the deeper-, colder-water-dwelling Mediterranean and Atlantic squids--are known to recruit luminous bacteria into light organ symbioses. The light organ symbiont of Euprymna spp. is Vibrio fischeri, but until now, the light organ symbionts of Sepiola spp. have remained inadequately identified. We used a combination of molecular and physiological characteristics to reveal that the light organs of Sepiola affinis and Sepiola robusta contain a mixed population of Vibrio logei and V. fischeri, with V. logei comprising between 63 and 100% of the bacteria in the light organs that we analyzed. V. logei had not previously been known to exist in such symbioses. In addition, this is the first report of two different species of luminous bacteria co-occurring within a single light organ. The luminescence of these symbiotic V. logei strains, as well as that of other isolates of V. logei tested, is reduced when they are grown at temperatures above 20 degrees C, partly due to a limitation in the synthesis of aliphatic aldehyde, a substrate of the luminescence reaction. In contrast, the luminescence of the V. fischeri symbionts is optimal above 24 degrees C and is not enhanced by aldehyde addition. Also, V. fischeri strains were markedly more successful than V. logei at colonizing the light organs of juvenile Euprymna scolopes, especially at 26 degrees C. These findings have important implications for our understanding of the ecological dynamics and evolution of cooperative, and perhaps pathogenic, associations of Vibrio spp. with their animal hosts.},
}
@article {pmid9336902,
year = {1997},
author = {Makemson, JC and Fulayfil, NR and Landry, W and Van Ert, LM and Wimpee, CF and Widder, EA and Case, JF},
title = {Shewanella woodyi sp. nov., an exclusively respiratory luminous bacterium isolated from the Alboran Sea.},
journal = {International journal of systematic bacteriology},
volume = {47},
number = {4},
pages = {1034-1039},
doi = {10.1099/00207713-47-4-1034},
pmid = {9336902},
issn = {0020-7713},
mesh = {Base Composition ; DNA, Bacterial/*analysis ; Fatty Acids/analysis ; Gram-Negative Facultatively Anaerobic Rods/chemistry/*classification/*genetics/physiology/ultrastructure ; Humans ; Luminescent Measurements ; Phylogeny ; Polymerase Chain Reaction ; RNA, Ribosomal, 16S/*analysis ; *Water Microbiology ; },
abstract = {Thirty-four strains of nonfermentative, respiratory, luminous bacteria were isolated from samples of squid ink and seawater from depths of 200 to 300 m in the Alboran Sea. Although these strains had a few properties similar to properties of Shewanella (Alteromonas) hanedai, they did not cluster phenotypically with any previously described bacterium. The nucleotide sequence of a 740-bp segment of luxA was not homologous with other known luxA sequences but clustered with the luxA sequences of Shewanella hanedai, Vibrio logei, Vibrio fischeri, and Photobacterium species. The 16S RNA gene from two strains was sequenced and was found to be most closely related to the S. hanedai 16S RNA gene. Based on the differences observed, we describe the new isolates as members of new species, Shewanella woodyi sp. nov. Strain ATCC 51908 (= MS32) is the type strain of this new species.},
}
@article {pmid28581841,
year = {1997},
author = {Hanlon, RT and Claes, MF and Ashcraft, SE and Dunlap, PV},
title = {Laboratory Culture of the Sepiolid Squid Euprymna scolopes: A Model System for Bacteria-Animal Symbiosis.},
journal = {The Biological bulletin},
volume = {192},
number = {3},
pages = {364-374},
doi = {10.2307/1542746},
pmid = {28581841},
issn = {1939-8697},
abstract = {The small Hawaiian sepiolid Euprymna scolopes, with its symbiotic luminous bacterium Vibrio fischeri, was cultured through one complete life cycle in 4 months. Paralarval squid hatchlings were actively planktonic for the first 20-30 days, after which they settled and assumed the typical adult mode of nocturnal activity and diurnal quiescence. Squids were aggressive predators that preferred actively swimming prey up to 2-4 times their size; the only diet that yielded good survival and rapid growth for paralarvae was large adult mysids. Survival to settlement was 73% on this diet, whereas it was 0%-17% on controls and three other diets. Paralarvae initially lacked both detectable luminescence and V. fischeri cells in their incipient light organs; all remaining stages produced luminescence, and their light organs were colonized by apparently pure cultures of > 105 V. fischeri typical of E. scolopes symbiont strains. Survival from settlement to sexual maturity was 76%. Mating and egg laying commenced at 2 months, yet attempts to culture the next laboratory generation of hatchlings were not as successful. The results indicate that the host organism of this symbiosis can soon be cultured with consistency through its brief life cycle, thus opening new avenues of research into developmental aspects of this symbiosis.},
}
@article {pmid9218761,
year = {1997},
author = {Ottemann, KM and Miller, JF},
title = {Roles for motility in bacterial-host interactions.},
journal = {Molecular microbiology},
volume = {24},
number = {6},
pages = {1109-1117},
pmid = {9218761},
issn = {0950-382X},
support = {AI38417/AI/NIAID NIH HHS/United States ; },
mesh = {Animals ; *Bacterial Physiological Phenomena ; Decapodiformes/microbiology ; Humans ; Intestinal Mucosa/microbiology ; Trout/microbiology ; Urinary Tract/microbiology ; Vibrio/physiology ; },
abstract = {The ability to move in a directed manner may confer distinct advantages upon host-adapted prokaryotes. Potential benefits of motility include increased efficiency of nutrient acquisition, avoidance of toxic substances, the ability to translocate to preferred hosts and access optimal colonization sites within them, and dispersal in the environment during the course of transmission. The costs of motility also may be significant. These include the metabolic burden of synthesizing flagellar components, the energetic expense of fuelling flagellar motors and the presentation of polymeric and highly antigenic targets to the immune system. It is therefore not surprising that synthesis of the motility apparatus is usually subject to strict control. Studies of a variety of bacterial-host interactions demonstrate roles for motility, and its regulation, at points throughout the infectious cycle.},
}
@article {pmid16535505,
year = {1997},
author = {Svitil, AL and Chadhain, S and Moore, JA and Kirchman, DL},
title = {Chitin Degradation Proteins Produced by the Marine Bacterium Vibrio harveyi Growing on Different Forms of Chitin.},
journal = {Applied and environmental microbiology},
volume = {63},
number = {2},
pages = {408-413},
pmid = {16535505},
issn = {0099-2240},
abstract = {Relatively little is known about the number, diversity, and function of chitinases produced by bacteria, even though chitin is one of the most abundant polymers in nature. Because of the importance of chitin, especially in marine environments, we examined chitin-degrading proteins in the marine bacterium Vibrio harveyi. This bacterium had a higher growth rate and more chitinase activity when grown on (beta)-chitin (isolated from squid pen) than on (alpha)-chitin (isolated from snow crab), probably because of the more open structure of (beta)-chitin. When exposed to different types of chitin, V. harveyi excreted several chitin-degrading proteins into the culture media. Some chitinases were present with all of the tested chitins, while others were unique to a particular chitin. We cloned and identified six separate chitinase genes from V. harveyi. These chitinases appear to be unique based on DNA restriction patterns, immunological data, and enzyme activity. This marine bacterium and probably others appear to synthesize separate chitinases for efficient utilization of different forms of chitin and chitin by-products.},
}
@article {pmid8942994,
year = {1996},
author = {Weis, VM and Small, AL and McFall-Ngai, MJ},
title = {A peroxidase related to the mammalian antimicrobial protein myeloperoxidase in the Euprymna-Vibrio mutualism.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {93},
number = {24},
pages = {13683-13688},
pmid = {8942994},
issn = {0027-8424},
mesh = {Animals ; Antibodies ; Cross Reactions ; DNA, Complementary ; Decapodiformes/*enzymology/*microbiology ; Electrophoresis, Polyacrylamide Gel ; Humans ; Immunoblotting ; Mammals ; Neutrophils/enzymology ; Organ Specificity ; Peroxidase/isolation & purification/*metabolism ; Peroxidases/biosynthesis/isolation & purification/*metabolism ; Symbiosis ; Vibrio/*physiology ; },
abstract = {Many animal-bacteria cooperative associations occur in highly modified host organs that create a unique environment for housing and maintaining the symbionts. It has been assumed that these specialized organs develop through a program of symbiosis-specific or -enhanced gene expression in one or both partners, but a clear example of this process has been lacking. In this study, we provide evidence for the enhanced production of an enzyme in the symbiotic organ of the squid Euprymna scolopes, which harbors a culture of the luminous bacterium Vibrio fischeri. Our data show that this enzyme has a striking biochemical similarity to mammalian myeloperoxidase (MPO; EC 1.11.17), an antimicrobial dianisidine peroxidase that occurs in neutrophils. MPO and the squid peroxidase catalyze the same reaction, have similar apparent subunit molecular masses, and a polyclonal antibody to native human MPO specifically localized a peroxidase-like protein to the bacteria-containing regions of the symbiotic organ. We also provide evidence that a previously described squid cDNA encodes the protein (LO4) that is responsible for the observed dianisidine peroxidase activity. An antibody made against a fragment of LO4 immunoprecipiated dianisidine peroxidase activity from extracts of the symbiotic organ, and reacted against these extracts and human MPO in Western blot analysis. These data suggest that related biochemical mechanisms for the control of bacterial number and growth operate in associations that are as functionally diverse as pathogenesis and mutualism, and as phylogenetically distant as molluscs and mammals.},
}
@article {pmid8917081,
year = {1996},
author = {Visick, KG and Ruby, EG},
title = {Construction and symbiotic competence of a luxA-deletion mutant of Vibrio fischeri.},
journal = {Gene},
volume = {175},
number = {1-2},
pages = {89-94},
pmid = {8917081},
issn = {0378-1119},
mesh = {Animals ; Decapodiformes/*microbiology/physiology ; Electroporation ; Escherichia coli/*genetics ; Genetic Vectors ; Luciferases/*genetics ; *Luminescent Measurements ; Mutagenesis, Insertional/*methods ; Symbiosis/*genetics ; Transfection ; Transformation, Bacterial/*genetics ; Vibrio/*genetics/physiology ; },
abstract = {Bioluminescence by the squid Euprymna scolopes requires colonization of its light organ by the symbiotic luminous bacterium Vibrio fischeri. Investigation of the genetic determinants underlying bacterial symbiotic competence in this system has necessitated the continuing establishment and application of molecular genetic techniques in V. fischeri. We developed a procedure for the introduction of plasmid DNA into V. fischeri by electroporation, and isolated a mutant strain that overcame the apparent restriction barrier between V. fischeri and Escherichia coli. Using the technique of electroporation in combination with that of gene replacement, we constructed a non-luminous strain of V. fischeri (delta luxA::erm). In addition, we used the transducing phage rp-1 for the first time to transfer a chromosomal antibiotic resistance marker to another strain of V. fischeri. The luxA mutant was able to colonize E. scolopes as quickly and to the same extent as wild type. This result suggested that, at least during the initial stages of colonization, luminescence per se is not an essential factor for the symbiotic infection.},
}
@article {pmid8668993,
year = {1996},
author = {Pennisi, E},
title = {Evolutionary and systematic biologists converge.},
journal = {Science (New York, N.Y.)},
volume = {273},
number = {5272},
pages = {181-182},
pmid = {8668993},
issn = {0036-8075},
mesh = {Animals ; *Biological Evolution ; *Biology ; *Classification ; Decapodiformes/microbiology ; Societies, Scientific ; Symbiosis ; Vibrio/physiology ; },
}
@article {pmid8905092,
year = {1996},
author = {Ruby, EG},
title = {Lessons from a cooperative, bacterial-animal association: the Vibrio fischeri-Euprymna scolopes light organ symbiosis.},
journal = {Annual review of microbiology},
volume = {50},
number = {},
pages = {591-624},
doi = {10.1146/annurev.micro.50.1.591},
pmid = {8905092},
issn = {0066-4227},
mesh = {Animals ; Cell Communication ; Cell Differentiation ; Decapodiformes/anatomy & histology/growth & development/*microbiology ; *Luminescent Measurements ; Molecular Biology ; Species Specificity ; Symbiosis/*physiology ; Vibrio/*physiology ; },
abstract = {Although the study of microbe-host interactions has been traditionally dominated by an interest in pathogenic associations, there is an increasing awareness of the importance of cooperative symbiotic interactions in the biology of many bacteria and their animal and plant hosts. This review examines a model system for the study of such symbioses, the light organ association between the bobtail squid Euprymna scolopes and the marine luminous bacterium Vibrio fischeri. Specifically, the initiation, establishment, and persistence of the benign bacterial infection of the juvenile host light organ are described, as are efforts to understand the mechanisms underlying this specific colonization program. Using molecular genetic techniques, mutant strains of V. fischeri have been constructed that are defective at specific stages of the development of the association. Some of the lessons that these mutants have begun to teach us about the complex and long-term nature of this cooperative venture are summarized.},
}
@article {pmid29244576,
year = {1995},
author = {Doino, JA and McFall-Ngai, MJ},
title = {A Transient Exposure to Symbiosis-Competent Bacteria Induces Light Organ Morphogenesis in the Host Squid.},
journal = {The Biological bulletin},
volume = {189},
number = {3},
pages = {347-355},
doi = {10.2307/1542152},
pmid = {29244576},
issn = {1939-8697},
abstract = {Recent studies of the symbiotic association between the Hawaiian sepiolid squid Euprymna scolopes and the luminous bacterium Vibrio fischeri have shown that colonization of juvenile squid with symbiosis-competent bacteria induces morphogenetic changes of the light organ. These changes occur over a 4-day period and include cell death and tissue regression of the external ciliated epithelium. In the absence of bacterial colonization, morphogenesis does not occur. To determine whether the bacteria must be present throughout the morphogenetic process, we used the antibiotic chloramphenicol to clear the light organ of bacteria at various times during the initial colonization. We provide evidence in this study that a transient, 12-hour exposure to symbiosis-competent bacteria is necessary and sufficient to induce tissue regression in the light organ over the next several days. Further, we show that successful entrance into the light organ is necessary to induce morphogenesis, suggesting that induction results from bacterial interaction with internal crypt cells and not with the external ciliated epithelium. Finally, no difference in development was observed when the light organ was colonized by a mutant strain of V. fischeri that did not produce autoinducer, a potential light organ morphogen.},
}
@article {pmid7860584,
year = {1995},
author = {Boettcher, KJ and Ruby, EG},
title = {Detection and quantification of Vibrio fischeri autoinducer from symbiotic squid light organs.},
journal = {Journal of bacteriology},
volume = {177},
number = {4},
pages = {1053-1058},
pmid = {7860584},
issn = {0021-9193},
mesh = {4-Butyrolactone/*analogs & derivatives/analysis ; Animals ; Biological Assay ; Decapodiformes/anatomy & histology/*microbiology ; Diffusion ; Epithelium/physiology ; *Luminescent Measurements ; Symbiosis/*physiology ; Vibrio/*physiology ; },
abstract = {Vibrio fischeri is the specific light organ symbiont of the sepiolid squid species Euprymna scolopes and Euprymna morsei. Both species of squid are luminescent by virtue of their bacterial symbionts, but the natural symbionts of E. scolopes do not produce visible luminescence in laboratory culture. The primary cause of this depressed luminescence by E. scolopes symbionts in culture was found to be the production of relatively low levels of V. fischeri autoinducer, a positive transcriptional coregulator of the lux regulon, identified as N-(3-oxohexanoyl) homoserine lactone. Concentrations of autoinducer activity produced by these symbionts in culture were quantified and found to be at least 10-fold lower than those produced by E. morsei isolates (which are visibly luminous outside the association) and perhaps 10,000-fold lower than those of the brightest V. fischeri strains. Despite the differences in their symbiont strains, the intact light organs of the two species of squid contained comparable amounts of extractable autoinducer activity (between 100 and 200 pg per adult animal). The chromatographic behavior of this autoinducer activity on reverse-phase high-performance liquid chromatography was consistent with its presumptive identification as V. fischeri autoinducer. Within the 5-microliter volume of the epithelial core of the light organ in which the symbiotic V. fischeri strains are housed, these amounts would result in an effective autoinducer concentration of at least 100 nM. Because these levels are over 40-fold higher than the concentration needed for the induction of luminescence of bacteria in culture, we conclude that the inherent degree of autoinducer production by strains of V. fischeri may not influence their effectiveness as light organ symbionts. Furthermore, this study provides the first direct evidence that the phenomenon of cell density-dependent autoinduction, discovered and described first for laboratory cultures of V. fischeri but believed to be a general phenomenon in many species of host-associated symbionts and pathogens, is in fact a consequence of bacterial colonizations of host tissues.},
}
@article {pmid16534910,
year = {1995},
author = {Lee, K and Ruby, EG},
title = {Symbiotic Role of the Viable but Nonculturable State of Vibrio fischeri in Hawaiian Coastal Seawater.},
journal = {Applied and environmental microbiology},
volume = {61},
number = {1},
pages = {278-283},
pmid = {16534910},
issn = {0099-2240},
abstract = {To achieve functional bioluminescence, the developing light organ of newly hatched juveniles of the Hawaiian squid Euprymna scolopes must become colonized by luminous, symbiosis-competent Vibrio fischeri present in the ambient seawater. This benign infection occurs rapidly in animals placed in seawater from the host's natural habitat. Therefore, it was surprising that colony hybridization studies with a V. fischeri-specific luxA gene probe indicated the presence of only about 2 CFU of V. fischeri per ml of this infective seawater. To examine this paradox, we estimated the total concentration of V. fischeri cells present in seawater from the host's habitat in two additional ways. In the first approach, the total bacterial assemblage in samples of seawater was collected on polycarbonate membrane filters and used as a source of both a crude cell lysate and purified DNA. These preparations were then assayed by quantitative DNA-DNA hybridization with the luxA gene probe. The results suggested the presence of between 200 and 400 cells of V. fischeri per ml of natural seawater, a concentration more than 100 times that revealed by colony hybridization. In the second approach, we amplified V. fischeri-specific luxA sequences from microliter volumes of natural seawater by PCR. Most-probable-number analyses of the frequency of positive PCR results from cell lysates in these small volumes gave an estimate of the concentration of V. fischeri luxA gene targets of between 130 and 1,680 copies per ml. From these measurements, we conclude that in their natural seawater environment, the majority of V. fischeri cells become nonculturable while remaining viable and symbiotically infective. Experimental studies indicated that V. fischeri cells suspended in natural Hawaiian seawater enter such a state within a few days.},
}
@article {pmid7961462,
year = {1994},
author = {Graf, J and Dunlap, PV and Ruby, EG},
title = {Effect of transposon-induced motility mutations on colonization of the host light organ by Vibrio fischeri.},
journal = {Journal of bacteriology},
volume = {176},
number = {22},
pages = {6986-6991},
pmid = {7961462},
issn = {0021-9193},
mesh = {Animals ; Cell Movement/*genetics ; Crosses, Genetic ; Decapodiformes/anatomy & histology/*microbiology ; Flagella/genetics/ultrastructure ; Light ; Mutagenesis, Insertional ; Mutation ; Selection, Genetic ; Symbiosis/genetics/*physiology ; Vibrio/genetics/growth & development/*physiology/ultrastructure ; },
abstract = {Vibrio fischeri is found both as a free-living bacterium in seawater and as the specific, mutualistic light organ symbiont of several fish and squid species. To identify those characteristics of symbiosis-competent strains that are required for successful colonization of the nascent light organ of juvenile Euprymna scolopes squids, we generated a mutant pool by using the transposon Mu dI 1681 and screened this pool for strains that were no longer motile. Eighteen independently isolated nonmotile mutants that were either flagellated or nonflagellated were obtained. In contrast to the parent strain, none of these nonmotile mutants was able to colonize the juvenile squid light organ. The flagellated nonmotile mutant strain NM200 possessed a bundle of sheathed polar flagella indistinguishable from that of the wild-type strain, indicating that the presence of flagella alone is not sufficient for colonization and that it is motility itself that is required for successful light organ colonization. This study identifies motility as the first required symbiotic phenotype of V. fischeri.},
}
@article {pmid7924980,
year = {1994},
author = {Montgomery, MK and McFall-Ngai, M},
title = {Bacterial symbionts induce host organ morphogenesis during early postembryonic development of the squid Euprymna scolopes.},
journal = {Development (Cambridge, England)},
volume = {120},
number = {7},
pages = {1719-1729},
pmid = {7924980},
issn = {0950-1991},
mesh = {Animals ; Cell Death ; Cell Differentiation/physiology ; Decapodiformes/*physiology/ultrastructure ; Epithelium/physiology/ultrastructure ; Microscopy, Electron, Scanning ; Models, Biological ; Morphogenesis/physiology ; Symbiosis/*physiology ; Vibrio/*physiology ; },
abstract = {The mutualistic association between the squid Euprymna scolopes and the bacterium Vibrio fischeri is an emerging experimental system for the study of the influence of bacteria on animal development. Taking advantage of the ability to raise both this host and its microbial partner independently under laboratory conditions, we describe the effects of bacterial interactions on morphogenesis of the juvenile host symbiotic organ. Our results show that bacteria are essential for normal postembryonic development of the symbiotic organ, which involves changes in both the surface epithelium and the epithelial tissue within the organ where the bacterial culture will take up residence. Cell death induced by exposure to symbiotic V. fischeri results in the regression of a complex ciliated surface epithelium, a tissue that apparently functions to facilitate inoculation of the juvenile organ with the appropriate specific bacterial species. Regression of this tissue begins within hours of exposure to symbiosis-competent bacteria and progresses over the next 5 days, at which time full regression is complete, resulting in a symbiotic organ whose epithelial surface resembles that of the fully mature organ. Moreover, symbiosis-competent bacteria induce modification of the epithelial cells of the crypts that will house these symbionts; these cells undergo significant changes in shape and size in response to interactions with symbiotic V. fischeri. In contrast, we find that when these tissues are not exposed to the proper bacterial symbionts they remain in a state of arrested morphogenesis, a condition that can be rescued by interactions with symbionts. The results of these studies are the first experimental data demonstrating that a specific bacterial symbiont can play an inductive role in animal development.},
}
@article {pmid16349257,
year = {1994},
author = {Lee, KH and Ruby, EG},
title = {Effect of the Squid Host on the Abundance and Distribution of Symbiotic Vibrio fischeri in Nature.},
journal = {Applied and environmental microbiology},
volume = {60},
number = {5},
pages = {1565-1571},
pmid = {16349257},
issn = {0099-2240},
abstract = {Euprymna scolopes, a Hawaiian species of bioluminescent squid, harbors Vibrio fischeri as its specific light organ symbiont. The population of symbionts grew inside the adult light organ with an average doubling time of about 5 h, which produced an excess of cells that were expelled into the surrounding seawater on a diurnal basis at the beginning of each period of daylight. These symbionts, when expelled into the ambient seawater, maintain or slightly increase their numbers for at least 24 h. Hence, locations inhabited by their hosts periodically receive a daily input of symbiotic V. fischeri cells and, as a result, become significantly enriched with these bacteria. As estimated by hybridization with a species-specific luxA gene probe, the typical number of V. fischeri CFU, both in the water column and in the sediments of E. scolopes habitats, was as much as 24 to 30 times that in similar locations where squids were not observed. In addition, the number of symbiotic V. fischeri CFU in seawater samples that were collected along a transect through Kaneohe Bay, Hawaii, decreased as a function of the distance from a location inhabited by E. scolopes. These findings constitute evidence for the first recognized instance of the abundance and distribution of a marine bacterium being driven primarily by its symbiotic association with an animal host.},
}
@article {pmid8144466,
year = {1994},
author = {Lee, KH and Ruby, EG},
title = {Competition between Vibrio fischeri strains during initiation and maintenance of a light organ symbiosis.},
journal = {Journal of bacteriology},
volume = {176},
number = {7},
pages = {1985-1991},
pmid = {8144466},
issn = {0021-9193},
mesh = {Animals ; Decapodiformes/growth & development/*microbiology ; Genetic Variation ; *Luminescent Measurements ; *Selection, Genetic ; Siderophores/biosynthesis ; *Symbiosis ; Vibrio/classification/genetics/*growth & development/metabolism ; },
abstract = {Colonization of the light-emitting organ of the Hawaiian squid Euprymna scolopes is initiated when the nascent organ of a newly hatched squid becomes inoculated with Vibrio fischeri cells present in the ambient seawater. Although they are induced for luminescence in the light organ, these symbiotic strains are characteristically non-visibly luminous (NVL) when grown in laboratory culture. The more typical visibly luminous (VL) type of V. fischeri co-occurs in Hawaiian seawater with these NVL strains; thus, two phenotypically distinct groups of this species potentially have access to the symbiotic niche, yet only the NVL ones are found there. In laboratory inoculation experiments, VL strains, when presented in pure culture, showed the same capability for colonizing the light organ as NVL strains. However, in experiments with mixed cultures composed of both VL and NVL strains, the VL ones were unable to compete with the NVL ones and did not persist within the light organ as the symbiosis became established. In addition, NVL strains entered light organs that had already been colonized by VL strains and displaced them. The mechanism underlying the symbiotic competitiveness exhibited by NVL strains remains unknown; however, it does not appear to be due to a higher potential for siderophore activity. While a difference in luminescence phenotype between VL and NVL strains in culture is not likely to be significant in the symbiosis, it has helped identify two distinct groups of V. fischeri that express different colonization capabilities in the squid light organ. This competitive difference provides a useful indication of important traits in light organ colonization.},
}
@article {pmid29300544,
year = {1993},
author = {Weis, VM and Montgomery, MK and McFall-Ngai, MJ},
title = {Enhanced Production of ALDH-Like Protein in the Bacterial Light Organ of the Sepiolid Squid Euprymna scolopes.},
journal = {The Biological bulletin},
volume = {184},
number = {3},
pages = {309-321},
doi = {10.2307/1542449},
pmid = {29300544},
issn = {1939-8697},
abstract = {We localized one or more aldehyde dehydrogenase (ALDH)-like proteins in the bacterially bioluminescent light organ of the sepiolid squid Euprymna scolopes, and determined the temporal changes in expression through normal light organ development. Our previous studies have revealed that 70% of the total protein in the light organ lens of adult animals is comprised of an ALDH-like protein, which we called L-crystallin. In the present study, antibodies raised to this protein were used in immunocytochemical analyses which showed that, in adult light organ lens cells, ALDH-like protein was localized to the cytoplasm, but not to the nuclei or mitochondria. Labeling in adult tissue was also found in moderate abundance in the ciliated duct epithelium, a tissue that is in direct contact with the bacterial symbionts. To determine the spatial and temporal onset of expression of ALDH-like protein(s), we examined light organs from juveniles at developmental stages before and after the differentiation of lens cells, which begins approximately 7-10 days after hatching. In 5-day symbiotic juvenile light organs, ALDH-like protein was not detected at levels significantly above those in non-symbiotic tissue of the same animals. However, expression of ALDH-like protein began within 10 days after hatching, seen first in a few cells of the ciliated duct, adjacent to the symbiont-containing tissue and in a few differentiated cells of the anterior presumptive light organ lens. These data suggest that, during normal development, induction of one or more ALDH-like proteins occurs simultaneously in both the lens and ciliated duct soon after the differentiation of lens cells.},
}
@article {pmid29300543,
year = {1993},
author = {Montgomery, MK and McFall-Ngai, M},
title = {Embryonic Development of the Light Organ of the Sepiolid Squid Euprymna scolopes Berry.},
journal = {The Biological bulletin},
volume = {184},
number = {3},
pages = {296-308},
doi = {10.2307/1542448},
pmid = {29300543},
issn = {1939-8697},
abstract = {The sepiolid squid Euprymna scolopes maintains luminous bacterial symbionts of the species Vibrio fischeri in a bilobed light organ partially embedded in the ventral surface of the ink sac. Anatomical and ultrastructural observations of the light organ during embryogenesis indicate that the organ begins development as a paired proliferation of the mesoderm of the hindgut-ink sac complex. Three-dimensional reconstruction of the incipient light organ of a newly hatched juvenile revealed the presence of three pairs of sacculate crypts, each crypt joined to a pore on the surface of the light organ by a ciliated duct. The crypts, which become populated with bacterial symbionts within hours after the juvenile hatches, appear to result from sequential paired invaginations of the surface epithelium of the hindgut-ink sac complex during embryogenesis. A pair of anterior and a pair of posterior ciliated epithelial appendages, which may facilitate infection of the incipient light organ with symbiotic bacteria, develop by extension and growth of the surface epithelium. The ink sac and reflector develop dorsal to the crypts and together function to direct luminescence ventrally. These two accessory tissues are present at the time of hatching, although changes in their overall structure accompany growth and maturation of the light organ. A third accessory tissue, the muscle-derived lens, appears during post-hatch maturation of the light organ.},
}
@article {pmid8439236,
year = {1993},
author = {Ruby, EG and Asato, LM},
title = {Growth and flagellation of Vibrio fischeri during initiation of the sepiolid squid light organ symbiosis.},
journal = {Archives of microbiology},
volume = {159},
number = {2},
pages = {160-167},
pmid = {8439236},
issn = {0302-8933},
mesh = {Animals ; Decapodiformes/anatomy & histology/growth & development/*microbiology ; Flagella/*ultrastructure ; Luminescent Measurements ; Microscopy, Electron ; *Symbiosis ; Vibrio/classification/cytology/*growth & development/physiology ; },
abstract = {A pure culture of the luminous bacterium Vibrio fischeri is maintained in the light-emitting organ of the sepiolid squid Euprymna scolopes. When the juvenile squid emerges from its egg it is symbiont-free and, because bioluminescence is part of an anti-predatory behavior, therefore must obtain a bacterial inoculum from the surrounding environment. We document here the kinetics of the process by which newly hatched juvenile squids become infected by symbiosis-competent V. fischeri. When placed in seawater containing as few as 240 colony-forming-units (CFU) per ml, the juvenile became detectably bioluminescent within a few hours. Colonization of the nascent light organ was initiated with as few as 1 to 10 bacteria, which rapidly began to grow at an exponential rate until they reached a population size of approximately 10(5) cells by 12 h after the initial infection. Subsequently, the number of bacteria in the established symbiosis was maintained essentially constant by a combination of both a > 20-fold reduction in bacterial growth rate, and an expulsion of excess bacteria into the surrounding seawater. While V. fischeri cells are normally flagellated and motile, these bacteria did not elaborate these appendages once the symbiosis was established; however, they quickly began to synthesize flagella when they were removed from the light organ environment. Thus, two important biological characteristics, growth rate and flagellation, were modulated during establishment of the association, perhaps as part of a coordinated series of symbiotic responses.},
}
@article {pmid1629148,
year = {1992},
author = {Ruby, EG and McFall-Ngai, MJ},
title = {A squid that glows in the night: development of an animal-bacterial mutualism.},
journal = {Journal of bacteriology},
volume = {174},
number = {15},
pages = {4865-4870},
pmid = {1629148},
issn = {0021-9193},
mesh = {Animals ; Decapodiformes/*physiology ; Light ; *Symbiosis ; Vibrio/*physiology ; },
}
@article {pmid1624432,
year = {1992},
author = {Gray, KM and Greenberg, EP},
title = {Physical and functional maps of the luminescence gene cluster in an autoinducer-deficient Vibrio fischeri strain isolated from a squid light organ.},
journal = {Journal of bacteriology},
volume = {174},
number = {13},
pages = {4384-4390},
pmid = {1624432},
issn = {0021-9193},
mesh = {4-Butyrolactone/*analogs & derivatives/metabolism/pharmacology ; Animals ; Base Sequence ; Chromosomes, Bacterial ; Cloning, Molecular ; DNA, Bacterial/genetics/isolation & purification ; Decapodiformes/microbiology ; Escherichia coli/genetics/growth & development/physiology ; *Genes, Bacterial/drug effects ; Luminescent Measurements ; Molecular Sequence Data ; *Multigene Family/drug effects ; Oligonucleotide Probes ; Plasmids ; Restriction Mapping ; Vibrio/*genetics/isolation & purification/physiology ; },
abstract = {Vibrio fischeri ES114 is an isolate representing the specific bacterial light organ symbiont of the squid Euprymna scolopes. An interesting feature of this strain of V. fischeri is that it is visibly luminous within the light organ of the squid host but is nonluminous when grown under standard laboratory conditions. Luminescence can be restored in laboratory culture, however, by the addition of autoinducer, a species-specific inducer of the V. fischeri luminescence (lux) genes. Most other isolates of V. fischeri produce autoinducer in sufficient quantities to induce luminescence in laboratory culture. We have cloned an 8.8-kb DNA fragment from V. fischeri ES114 that encodes all of the functions necessary for luminescence in Escherichia coli in the absence of exogenous autoinducer. This DNA contains both of the recognized V. fischeri lux regulatory genes, one of which (luxI) directs E. coli to synthesize autoinducer. The organization of the individual lux genes within this DNA fragment appears to be the same as that in the other strains of V. fischeri studied; the restriction map of the V. fischeri ES114 lux DNA has diverged substantially, however, from the largely conserved maps of V. fischeri MJ1 and ATCC 7744. Although E. coli containing the V. fischeri ES114 lux DNA synthesizes considerable amounts of autoinducer, V. fischeri ES114 synthesizes autoinducer only in small amounts, even when transcription of the lux genes, including luxI, is activated by the addition of exogenous autoinducer. Nonetheless, transconjugants of V. fischeri ES114 that contain multicopy plasmids bearing the ES114 lux genes synthesize sufficient autoinducer to induce luminescence. These results suggest that V. fischeri ES11r does not lack a functional luxl, nor is it deficient in the ability to synthesize metabolic precursors for autoinducer synthesis.},
}
@article {pmid16348678,
year = {1992},
author = {Lee, KH and Ruby, EG},
title = {Detection of the Light Organ Symbiont, Vibrio fischeri, in Hawaiian Seawater by Using lux Gene Probes.},
journal = {Applied and environmental microbiology},
volume = {58},
number = {3},
pages = {942-947},
pmid = {16348678},
issn = {0099-2240},
abstract = {Symbiotic bacteria that inhabit the light-emitting organ of the Hawaiian squid Euprymna scolopes are distinctive from typical Vibrio fischeri organisms in that they are not visibly luminous when grown in laboratory culture. Therefore, the abundance of these bacteria in seawater samples cannot be estimated simply by identifying them among luminous colonies that arise on nutrient agar plates. Instead, we have used luxR and polymerase chain reaction generated luxA gene probes to identify both luminous and non-visibly luminous V. fischeri colonies by DNA-DNA hybridization. The probes were specific, hybridizing at least 50 to 100 times more strongly to immobilized DNAs from V. fischeri strains than to those of pure cultures of other related species. Thus, even non-visibly luminous V. fischeri colonies could be identified among colonies obtained from natural seawater samples by their probe-positive reaction. Bacteria in seawater samples, obtained either within or distant from squid habitats, were collected on membrane filters and incubated until colonies appeared. The filters were then observed for visibly luminous V. fischeri colonies and hybridized with the lux gene probes to determine the number of total V. fischeri colonies (both luminous and non-visibly luminous). We detected no significant differences in the abundance of luminous V. fischeri CFU in any of the water samples observed (=1 to 3 CFU/100 ml). However, probe-positive colonies of V. fischeri (up to 900 CFU/100 ml) were found only in seawater collected from within the natural habitats of the squids. A number of criteria were used to confirm that these probe-positive strains were indistinguishable from symbiotic V. fischeri. Therefore, the luxA and luxR gene probes were species specific and gave a reliable estimate of the number of culturable V. fischeri colonies in natural water samples.},
}
@article {pmid1962208,
year = {1991},
author = {McFall-Ngai, MJ and Ruby, EG},
title = {Symbiont recognition and subsequent morphogenesis as early events in an animal-bacterial mutualism.},
journal = {Science (New York, N.Y.)},
volume = {254},
number = {5037},
pages = {1491-1494},
pmid = {1962208},
issn = {0036-8075},
mesh = {Animals ; Decapodiformes/anatomy & histology/growth & development/*microbiology ; Luminescence ; *Symbiosis ; Vibrio/*physiology ; },
abstract = {Bacterial colonization of the developing light organ of the squid Euprymna scolopes is shown to be highly specific, with the establishment of a successful association resulting only when the juvenile host is exposed to seawater containing one of a subset of Vibrio fischeri strains. Before a symbiotic infection the organ has elaborate epithelial structures covered with cilia and microvilli that are involved in the transfer of bacteria to the incipient symbiotic tissue. These structures regressed within days following infection; however, they were retained in uninfected animals, suggesting that the initiation of symbiosis influences, and is perhaps a prerequisite for, the normal developmental program of the juvenile host.},
}
@article {pmid29314961,
year = {1990},
author = {McFall-Ngai, M and Montgomery, MK},
title = {The Anatomy and Morphology of the Adult Bacterial Light Organ of Euprymna scolopes Berry (Cephalopoda:Sepiolidae).},
journal = {The Biological bulletin},
volume = {179},
number = {3},
pages = {332-339},
doi = {10.2307/1542325},
pmid = {29314961},
issn = {1939-8697},
abstract = {The sepiolid squid, Euprymna scolopes, has a bilobed luminous organ in the center of the mantle cavity, associated with the ink sac. Luminous bacterial symbionts (Vibrio fischeri) are housed in narrow channels of host epithelial tissue. The channels of each lobe of the light organ empty into a ciliated duct, which is contiguous with the mantle cavity of the squid. Surrounding the symbiotic bacteria and their supportive host cells are host tissues recruited into the light organ system, including a muscle-derived lens and thick reflector that appear to permit the squid to control the quality of bacterial light emission.},
}
@article {pmid2163384,
year = {1990},
author = {Boettcher, KJ and Ruby, EG},
title = {Depressed light emission by symbiotic Vibrio fischeri of the sepiolid squid Euprymna scolopes.},
journal = {Journal of bacteriology},
volume = {172},
number = {7},
pages = {3701-3706},
pmid = {2163384},
issn = {0021-9193},
mesh = {Animals ; Culture Media ; Cyclic AMP/pharmacology ; Decapodiformes/microbiology ; Light ; Luminescent Measurements ; Species Specificity ; Symbiosis ; Vibrio/growth & development/isolation & purification/*physiology ; },
abstract = {Bioluminescent marine bacteria of the species Vibrio fischeri are the specific light organ symbionts of the sepiolid squid Euprymna scolopes. Although they share morphological and physiological characteristics with other strains of V. fischeri, when cultured away from the light organ association the E. scolopes symbionts depress their maximal luminescence over 1,000-fold. The primary cause of this reduced luminescence is the underproduction by these bacteria of luciferase autoinducer, a molecule involved in the positive transcriptional regulation of the V. fischeri lux operon. Such an absence of visible light production outside of the symbiotic association has not been previously reported among light organ symbionts of this or any other species of luminous bacteria. Levels of luminescence approaching those of the E. scolopes bacteria in the intact association can be restored by the addition of exogenous autoinducer to bacteria in laboratory culture and are affected by the presence of cyclic AMP. We conclude that some condition(s) specific to the internal environment of the light organ is necessary for maximal autoinduction of luminescence in the symbionts of this squid-bacterial association.},
}
@article {pmid4091566,
year = {1985},
author = {Molitoris, E and Joseph, SW and Krichevsky, MI and Sindhuhardja, W and Colwell, RR},
title = {Characterization and distribution of Vibrio alginolyticus and Vibrio parahaemolyticus isolated in Indonesia.},
journal = {Applied and environmental microbiology},
volume = {50},
number = {6},
pages = {1388-1394},
pmid = {4091566},
issn = {0099-2240},
mesh = {Animals ; Anti-Bacterial Agents/pharmacology ; Drug Resistance, Microbial ; Fishes ; Geography ; Indonesia ; Mollusca/microbiology ; Seasons ; Species Specificity ; Vibrio/classification/drug effects/*isolation & purification ; },
abstract = {Previous studies have shown that Vibrio alginolyticus and Vibrio parahaemolyticus can be isolated from similar types of marine samples. In this report, the results of an examination of 567 V. alginolyticus and V. parahaemolyticus strains, isolated from seawater in Jakarta Bay and from more than 30 types of seafood from markets in Jakarta, Indonesia, are presented. Most isolates were from mackerel, shrimp, or squid. Numerical taxonomic analyses clustered 337 isolates and three V. alginolyticus reference strains at S greater than or equal to 80%. These strains produced acid from sucrose, but only approximately 80% produced acetoin or grew in the presence of 10% NaCl. The frequency of occurrence of V. alginolyticus in seawater samples ranged from 0% (in February and March 1972) to 100% (in September and December 1972) and was highest in seafood samples from August to December 1972. A second cluster of 230 isolates and seven V. parahaemolyticus reference strains was observed at S greater than or equal to 82%. These strains did not produce acetoin or acid from sucrose, and approximately 20% grew in the presence of 10% NaCl. V. parahaemolyticus was detected in seawater samples each month, with the highest frequency of occurrence (83.3%) in May 1972. Twenty-nine K antigen serotypes were demonstrated in V. parahaemolyticus isolates, and another 40% were untypable. The modal antibiotic resistance pattern for each species included five drugs. Only 12% of the V. parahaemolyticus strains were Kanagawa positive, and 10% elicited fluid accumulation in ligated rabbit ileal loops. All of the 7 V. alginolyticus strains and 94 (70%) of the V. parahaemolyticus strains tested killed mice when inoculated intraperitoneally.(ABSTRACT TRUNCATED AT 250 WORDS)},
}
@article {pmid6735567,
year = {1984},
author = {Goh, KT and Lam, S and Kumarapathy, S and Tan, JL},
title = {A common source foodborne outbreak of cholera in Singapore.},
journal = {International journal of epidemiology},
volume = {13},
number = {2},
pages = {210-215},
pmid = {6735567},
issn = {0300-5771},
mesh = {Adolescent ; Adult ; Cholera/*epidemiology/transmission ; Decapodiformes/microbiology ; *Disease Outbreaks ; Female ; Food Handling ; *Food Microbiology ; Humans ; Male ; Singapore ; Transients and Migrants ; Vibrio cholerae ; },
abstract = {An epidemiological investigation of an outbreak of Vibrio cholerae 01, biotype El Tor, serotype Ogawa, phage type 1, confined to a group of foreign construction workers in Singapore is described. A total of 22 workers were confirmed to have cholera and another 15 had asymptomatic Vibrio cholerae 01 infection between 3 November and 11 November 1982. The source of infection was traced to contaminated seafood prepared at the construction site canteen where two food handlers were found to be infected with V. cholerae 01 (one symptomatic and the other asymptomatic). The incubation period of cholera in this outbreak ranged from 4 to 203 hours with a median of 38 hours. Only two workers had moderate to severe dehydration and required intravenous therapy. Early recognition of the outbreak and prompt implementation of control measures prevented the outbreak from spreading to other parts of Singapore.},
}
@article {pmid6865804,
year = {1983},
author = {Kuwae, T and Kurata, M},
title = {Chemical and biological properties of Lipopolysaccharides from symbiotic luminous bacteria from several luminous marine animals.},
journal = {Microbiology and immunology},
volume = {27},
number = {2},
pages = {137-149},
pmid = {6865804},
issn = {0385-5600},
mesh = {Adjuvants, Immunologic ; Animals ; Antibody Formation ; Electrophoresis, Polyacrylamide Gel ; Enterobacteriaceae/*physiology ; Immune Tolerance ; Lipopolysaccharides/analysis/*physiology ; *Luminescent Measurements ; Lymphocyte Activation ; Macrophages/immunology ; Mice ; Phagocytosis ; Polysaccharides, Bacterial/*physiology ; },
abstract = {The chemical and biological properties of lipopolysaccharides (LPS) in five strains of symbiotic luminous bacteria isolated from four species of luminous marine fishes, Coelorhynchus kishinouyei (CK-1), Chlorophthalmus albatrossis (CA-1), Ventrifossa garmani (VG-1), and Acropoma japonicum (AJ-1b), as well as from a luminous squid, Doryteuthis kensaki (DK-1) were examined. The LPS isolated from these symbiotic luminous bacteria were characterized by the absence of 2-keto-3-deoxyoctonate, known to be a basic component of the usual gram-negative bacterial LPS. All LPS from these symbiotic luminous bacteria upon electrophoresis in sodium dodecylsulfate polyacrylamide gel exhibited one or two clear main bands with high mobility, and one or two obscure minor bands with low mobility when stained with periodate-Schiff reagent. LPS from CA-1 and VG-1 exhibited similar electrophoretic patterns, whereas the electrophoretic patterns of the LPS from CK-1, AJ-1b, and DK-1 were easily distinguishable from each other. All these LPS also had similarly potent and diverse biological activities in regard to their adjuvanticity, immunosuppression, polyclonal effect, B-cell mitogenicity, and activation of the phagocytic function of macrophages.},
}
@article {pmid6820471,
year = {1982},
author = {Kuwae, T and Fukasawa, S and Sasaki, T and Kurata, M},
title = {Immunochemical comparisons among lipopolysaccharides from symbiotic luminous bacteria isolated from several luminous marine animals.},
journal = {Microbiology and immunology},
volume = {26},
number = {12},
pages = {1181-1186},
pmid = {6820471},
issn = {0385-5600},
mesh = {Animals ; Chemical Precipitation ; Decapodiformes/microbiology ; Fishes/*microbiology ; Immune Sera/pharmacology ; Immunodiffusion ; Immunoelectrophoresis ; *Light ; Lipopolysaccharides/*analysis ; Photobacterium/analysis/immunology ; Rabbits ; Symbiosis ; Vibrio/analysis/immunology ; },
}
@article {pmid6941738,
year = {1981},
author = {Nealson, K and Cohn, D and Leisman, G and Tebo, B},
title = {Co-evolution of luminous bacteria and their eukaryotic hosts.},
journal = {Annals of the New York Academy of Sciences},
volume = {361},
number = {},
pages = {76-91},
pmid = {6941738},
issn = {0077-8923},
mesh = {*Bacteria ; *Biological Evolution ; *Cells ; *Eukaryotic Cells ; Light ; Luminescent Measurements ; Organoids ; Symbiosis ; },
abstract = {Several species of three genera of luminous bacteria from marine and soil environments are known to form specific symbioses with fish, squid, urochordates, and nematodes. These bacteria contain a unique and easily detectable enzyme, bacterial luciferase, which allows the detection of the bacteria even when they cannot be cultured from animal tissue. The bacteria-animal associations vary; they range from transient, nonspecific gut symbionts in many fishes to highly specific, nonculturable, intracellular symbionts in pyrosomes. The study of these microbe-animal symbioses may allow understanding of the alterations that occur in the partners during the establishment of intracellular organelles. These studies are incomplete, in particular the level of partner integration, the nature of the metabolic exchange, the mechanism of transmission of symbionts to offspring, and the identification of the cellular inclusions as modified bacteria are not always known. However, the outline of what is likely to be a continuous evolutionary sequence of luminous bacterial symbionts with their various animal hosts is becoming clear. As more of these symbioses are studied, we anticipate that new systems will be found that represent states between those described here, and that the luminous bacteria will provide a living model for the gradual evolution from free-living microbes in intracellular organelles.},
}
@article {pmid351818,
year = {1977},
author = {Seng, LY and Jegathesan, M},
title = {A bacteriological study of some frozen and nonfrozen foods.},
journal = {The Southeast Asian journal of tropical medicine and public health},
volume = {8},
number = {4},
pages = {437-446},
pmid = {351818},
issn = {0125-1562},
mesh = {Animals ; Decapoda (Crustacea) ; Decapodiformes ; Escherichia coli/isolation & purification ; Food Handling/*standards ; *Food Microbiology ; Frozen Foods ; Humans ; Public Health ; Staphylococcus aureus/isolation & purification ; Vibrio parahaemolyticus/isolation & purification ; },
abstract = {Over a period of 19 months, a total of 331 food samples were submitted to the Food Section of the Bacteriology Division for bacteriological examination. These included 184 samples of frozen seafoods from exporters and 147 samples of fresh, nonfrozen foods from food caterers. The total bacterial count for frozen seafoods ranged from 1 x 10(2) to 2.98 x 10(6) per gm with a mean of 2.14 x 10(5) per gm. Coliforms, Escherichia coli and Staphylococcus aureus were present in 48.9%, 3.3% and 8.2% of the samples examined respectively. Two of the cooked prawn samples showed the presence of Vibrio parahaemolyticus. For the fresh, nonfrozen foods, the total bacterial count ranged from 1 x 10(2) to 3.87 x 10(6) per gm with a mean of 2.58 x 10(5) per gm. The examination also showed that 74.8% were coliform positive, 14.9% were E. coli positive, and 4.8% were S. aureus positive. V. parahaemolyticus was not isolated in any of the samples tested. Other pathogens, namely, Vibrio cholerae, Salmonella and Shigella were not isolated from any of the foods examined. The bacterial levels in these foods were determined and their sanitary and public health significance is discussed.},
}